Ark investigation uncovers federal searches of Tiburon license-plate data
- Kevin Hessel
- 2 hours ago
- 18 min read
In response, police chief admits 23 agencies potentially violated privacy and immigration laws when accessing system
After three months of refusing comment, Tiburon Police Chief Michelle Jean acknowledged in a Feb. 3 email that 23 agencies have conducted potentially illegal federal searches of the town’s automated license-plate camera database, including for immigration enforcement. The admission and department’s quiet December revisions to its oversight policies came in direct response to an Ark investigation that documented 475 federal searches by nine California agencies, raising significant questions about violations of state privacy laws and the town’s handling of driver data.
Jean called the searches an “unacceptable use of the town’s license-plate reader data,” acknowledging that California agencies “may have accessed the town’s data and potentially shared that data with federal immigration agencies” amid the Trump administration’s nationwide crackdown.
State law prohibits any sharing of camera data with private, out-of-state and federal agencies to protect Californians’ privacy, as well as the use of any state or local resources for federal immigration enforcement.
The Ark’s audit of public records from May through August — with detailed initial findings provided to Jean in October — found that the nine in-state agencies conducted searches involving the U.S. Marshals Service; the Drug Enforcement Administration; the Bureau of Alcohol, Tobacco, Firearms and Explosives; and other federal entities.
Jean’s acknowledgment of 14 additional agencies suggests dozens if not hundreds of additional federal searches over a longer period that also involved Immigration and Customs Enforcement or U.S. Customs and Border Protection.
She stated that “the actions of the Tiburon Police Department and our authorized (automated license-plate reader) users are fully compliant” in a claim that appears to defend the department’s handling of private data while asserting Tiburon’s own officers have not conducted illegal searches. However, Tiburon redacted relevant fields for searches made by its own officers, preventing The Ark from auditing those public records.
Despite acknowledging the potential violations, public records show Tiburon continued to expand the number of agencies with access to its database by 45% during its internal investigation, growing from 132 to 191 since July. That includes new access for several agencies previously identified by civil-liberties and media organizations as not complying with state law. None of the nine agencies identified by The Ark were removed, though the Iipay Nation of Santa Ysabel, Carlsbad and Salinas police departments no longer have access.
The expansion stands in stark contrast to other jurisdictions’ responses: Richmond shut down its Flock Safety cameras in December, Santa Cruz terminated its contract in January and Mountain View disabled all cameras last week, joining dozens of other agencies nationwide that turned off cameras or ended their relationships with Georgia-based Flock in recent months over illegal access, privacy concerns, abuse of data and company ethics.
That has included police use of cameras to track a woman who self-administered an abortion, to track protesters exercising constitutionally protected speech and to stalk private citizens, while reports show Flock secretly worked with federal immigration officials and illegally reinstalled cameras in jurisdictions that ordered them removed.
Mountain View Police Chief Mike Canfield announced Feb. 2 that all 30 Flock cameras in his jurisdiction were being disabled after discovering that hundreds of agencies had accessed its database in violation of city policies for more than a year.
“I personally no longer have confidence in this particular vendor,” Canfield told the Mountain View Voice, specifically citing Flock’s “lack of proactive disclosure” and that he “gave assurances to the community that I now know were not grounded in the Flock system’s actual practice.”
State law and Tiburon’s database searches
California enacted two laws to prevent the type of data sharing documented in Tiburon’s system. Senate Bill 34, enacted in 2016, bars direct access and the selling, sharing or transferring of camera-database information to nonstate agencies — meaning even in-state law-enforcement agencies can’t search Tiburon’s records and then hand off query results in what’s known as a side-entry or backdoor search. Senate Bill 54 of 2018 is the state’s sanctuary law, barring any use of state or local resources for federal immigration enforcement.
The California Department of Justice issued guidance on both laws in 2023 amid reports by media and civil-liberties groups that police agencies were refusing to comply with the laws and in some cases were actively working with federal immigration agencies.
“While this technology may be a helpful investigative tool, Californians must be able to trust that their information is being kept safe,” Attorney General Rob Bonta said at the time. “Today, we remind law enforcement of their responsibility to safeguard this data and ensure its use is consistent with state law.”
According to public records obtained and audited by The Ark, nine California law-enforcement agencies searched Tiburon’s former Motorola Vigilant and new Flock Safety automated license-plate reader databases for federal investigations throughout the May-August period.
Citrus Heights Police Department conducted 413 searches tagged for U.S. Postal Service investigations, which were also the subject of searches by the California Highway Patrol, Costa Mesa Police Department and Pasadena Police Department.
The Murrieta Police Department searched Tiburon’s camera database for an “atf investigation,” while the California Department of Corrections conducted multiple searches labeled “DEA T-III Investigation” and “USMS Fugitive Investigation,” for the Marshals Service. The Riverside County District Attorney also conducted searches marked “USMS Case.”
The Danville and Orange police departments conducted U.S. Department of Agriculture searches for “ebt fraud,” referring to government-issued debit cards that allow public-assistance recipients to buy groceries and other qualifying items.
The 14 additional agencies may include those that the ACLU and Electronic Frontier Foundation identified to the attorney general in January 2024 as either refusing to comply with SB 34 or failing to respond to compliance inquiries.
Tiburon was already sharing data with 12 of the 35 agencies identified by the ACLU and EFF when The Ark first requested public records. Those agencies conducted more than 172,000 searches of Tiburon’s database during the four-month review period — nearly 30% of the 576,000 external searches logged by the system. Since then, the department has added four more of those agencies, plus the San Francisco Police Department, which illegally conducted its own federal immigration searches and allowed out-of-state agencies to illegally search its own database more than 1.6 million times, the San Francisco Standard reported in September.
Jean did not address why Tiburon is both continuing to share with agencies publicly identified as not complying with state law while adding new ones.
Matt Cagle, technology and civil liberties director at the ACLU of Northern California, reviewed portions of The Ark’s audit and said the federal references and Tiburon’s refusal to explain them raise serious questions about both the searches and the town’s oversight responsibilities.
“Tiburon should be taking all the steps it can to make sure that people’s information and their locations are protected and not being misused by other agencies,” he said. “Those are questions that Tiburon should better understand because once this information leaves Tiburon, it can be used in many different ways, which is precisely why we have privacy laws that protect the locations of drivers here in California.”
New audit procedures adopted in December
Jean’s Feb. 3 response confirmed the town implemented its new audit procedures only after The Ark’s investigation and inquiries.
“At the time of your original (California Public Records Act) requests, dated July 30, 2025, and August 18, 2025, we were still in implementation stages with Flock,” Jean wrote. “Your requests prompted us to re-evaluate our policies, procedures and our data shares in that time of transition to ensure the new system is compliant with both state law and our local policies.”
However, the searches documented by The Ark in May and June occurred on Tiburon’s former Motorola system, predating the transition to Flock and unrelated to implementation issues with the new system. Jean did not address how the Flock transition affected oversight of searches on the Motorola system.
And while Jean asserted "the scrutiny of (license-plate) data-sharing increased just as the town was transitioning to Flock from its old (camera) system" last summer, civil liberties groups have been sounding alarm bells for years: "Neither local police departments, nor government officials, nor residents should blindly accept Flock’s model simply because it advances Flock’s bottom line, or because other jurisdictions have unwisely chosen to do so. We continue to believe that using Flock cameras should be opposed outright," the ACLU wrote in 2023.
Tiburon posted its updated plate-reader policy Dec. 4, and Jean said the new audit procedures require monthly reviews of both internal officer searches and external agency searches.
She said new safeguards specific to the Flock system included working with the company to “allow external searches only for valid reasons, such as burglary, theft, homicide (i.e. criminal cases)” and requiring all users to accept a disclaimer stating they must comply with California law.
If audits show potential violations, Jean said, the town now provides written notice to agencies and terminates access within 30 days if no adequate explanation is received, though that procedure is not specifically outlined in the written policy.
“Based on this protocol, in January, we contacted 23 agencies,” Jean said in her Feb. 3 response, which suggests the 30-day compliance-review period may still be open for those agencies.
While the new December policy requires monthly audits, the minimum standards represent a fraction of actual search activity.
The policy requires the network coordinator to “randomly select at least five detection browsing inquiries conducted by department employees, and detection browsing inquiries conducted by outside parties, during the preceding one-month period.”
External agencies conducted an average of 135,000 searches per month of the new Flock system in July and August, meaning a five-search audit would represent less than 0.004% of monthly activity.
While acknowledging that external agencies may have violated state law using Tiburon’s system, Jean said that, “consistent with other agencies,” the town will not be “publishing our external search audits online” without citing further justification.
For internal searches, the town will continue redacting search reasons for cases under investigation “to protect the integrity of the investigation,” but it will include officer names, which are redacted in the auto-reports generated by Flock, Jean said. Those will be posted monthly on the town’s website, where December’s internal audit is now online.
Jean said the town’s separate Flock-hosted transparency portal is now live after delays “due to incorrect information regarding the number of cameras in use,” though she did not address why Tiburon has actively disabled the live-audit feature for internal searches.
At least 17 other Bay Area jurisdictions display internal search activity in near real time.
New system generates detailed vehicle fingerprints — and suspicion
To national media attention, Tiburon in 2010 became one of the first towns in the U.S. to install fixed plate-reading cameras, while Belvedere followed in 2015. Both made the switch to Flock in July, following the Marin County Sheriff’s Office’s switch in early 2024.
In a September 2024 presentation to the Tiburon police chief’s Citizens Advisory Panel, the department touted Flock’s advantages, including advanced image-processing algorithms, ability to survey multiple lanes with fewer cameras, solar power eliminating the need for external power sources, faster maintenance response and lower overall costs versus the Motorola system.
The presentation noted that 80% of Bay Area law-enforcement agencies use Flock with 6,989 cameras functioning and 2,000 more planned, plus more than 1,000 cameras operated by private entities including commercial businesses, homeowners associations and apartment complexes. State law does not prevent California agencies from receiving and searching data from private, out-of-state or federal agencies through one-way, incoming shares.
While the Motorola system in practice captured only license-plate data, Flock’s system also creates detailed vehicle fingerprints including make, model and color of cars, whether plates are covered or missing and unique features such as roof racks, bumper stickers, dents and rust. Those markers allow a vehicle to be tracked even if plates are removed or changed.
Flock’s artificial intelligence also analyzes vehicles’ driving patterns through a feature called convoy analysis and alerts police if movements and associations suggest criminality. Civil-liberties advocates say the technology generates suspicion on a level approaching “Minority Report,” the novel-turned-film in which psychic technology is used to arrest and convict murderers before they commit a crime.
Public records show Tiburon and Belvedere made about 7.7 million and 1.8 million scans per year, respectively, in 2020, but just 0.01% of those provided a hit for illegal activity, meaning 99.99% of the retained geotagged, time-stamped movements of vehicles were not associated with any crime. When pieced together with plate data from other agencies, the always-on dragnet can give authorities a look into the daily routines of drivers, from where they live and work and where their children attend school to their religious and political activities.
“These systems are collecting data on everybody — not just people suspected of crimes, but everyone who drives through an intersection,” Cagle said. “The question is: What protections are in place to make sure that data is used responsibly? And what are the stakes for people’s privacy?
“When we aggregate more and more data, when you have systems that can analyze broad swaths of data to try and draw conclusions about people, whether those conclusions are accurate or not, the potential privacy harms are only compounded,” he said.
Town obscured camera locations, search records
The town’s resistance to transparency began in July, when Tiburon refused to disclose how many new Flock cameras the town operates or where they are located, departing from the town’s historical transparency under the former Motorola system. Capt. Jarrod Yee declined to disclose the number and location of the Flock cameras before Jean defended the secrecy in an August email, saying disclosure could help criminals defeat the system and lead to theft or vandalism.
Other Bay Area departments — including San Francisco, Los Altos Hills, Foster City and Morgan Hill — post maps of their camera locations directly on agency-operated transparency websites. Such agencies have cited public awareness as the deterrent, a position held by previous Tiburon police chiefs.
Tiburon twice attempted to deny The Ark’s public-records request for camera numbers and locations, initially giving vague responses before misciting state law and case law around disclosure obligations. After several exchanges, the town ultimately disclosed that it operates eight Flock cameras at the same locations previously covered by 12 Motorola cameras: two on Tiburon Boulevard at the town limits, between Blackfield and Bay Vista drives; two on northern Paradise Drive near town limits with Corte Madera; and four on the Bay Vista Drive intersections of the Cypress Hollow neighborhood that were added in 2022 to close a coverage gap.
Belvedere Police Chief Jason Wu immediately told The Ark the city’s six new Flock cameras remain in the same place as the previous system, with pairs staged at San Rafael Avenue and Lagoon Road, at Lagoon Road and Cove Road, and at Beach Road and Cove Road. The four Strawberry cameras include two on Tiburon Boulevard near the Redwood Highway frontage road and two at the southern end of the frontage road — one near the intersection with De Silva Island Drive and one near the intersection of Seminary Drive.
Tiburon’s resistance continued with search records.
The town initially obscured the reason column for all 576,000 external searches by outside agencies under the assertion that search reasons are investigative records exempt from disclosure. However, the California Public Records Act disallows broad categorical redaction and requires case-by-case justification for each withheld record. After several exchanges and a challenge for judicial review, the town agreed to unredact the external searches and redact only active local investigations — though the town ultimately never provided local search logs with partial redactions.
Tiburon officials remain silent
Jean appeared to explain her three-month refusal to comment by saying the town’s primary obligations were responding to The Ark’s records request and ensuring the new Flock system was working effectively while updating policies and procedures and training officers.
But other town officials also remained silent about the searches, apparently at the instruction of Town Attorney Ben Stock, who did not respond to email and phone requests for comment.
Town Manager Greg Chanis did not respond to a request for comment, including whether the Tiburon Town Council has been briefed on the federal searches or whether they represent a compliance failure or policy problem.
Mayor Jon Welner; Diversity Inclusion Task Force Vice Chair Tina Shah Paikeday, an at-large citizen representative to the board; and Hawi Awash, a citizen representative on both the Diversity Inclusion Task Force and the police chief’s Citizens Advisory Panel, also did not respond to requests for comment.
Colin Murray, a Citizens Advisory Panel member, provided the only response, saying in a Jan. 22 email that the panel is “merely advisory to the Tiburon Police Department” and “not overseeing operational issues, including data compliance.” He said Flock has not been discussed at the meetings he’s attended, noting he has missed a few.
In a follow-up email, Murray said he agreed “from a policy perspective the Flock data should not be shared with ICE, etc.” but offered no other comment on The Ark’s findings, the citizen-oversight role of the advisory panel or the department’s responsibilities to protect citizens’ data.
Late Jan. 29, Tiburon Councilmember Holli Thier, chair of the Diversity Inclusion Task Force, emailed in response to The Ark’s inquiries that “our town attorney has informed me that because this email alleges potential legal compliance issues, I cannot respond.”
Jean did not respond to Ark questions submitted Oct. 27, with an initial comment deadline of Nov. 6, or to a follow-up request made Nov. 7 and comment extensions to Jan. 13, Jan. 22 and Jan. 29. Her Feb. 3 email reply came just hours after The Ark failed to reach Stock by phone.
Part of state and national pattern
The federal searches of Tiburon’s database align with a statewide pattern in which dozens of California police agencies have refused to comply with sharing laws since the law was enacted a decade ago, as well as a nationwide pattern of Flock Safety abuses that have prompted a congressional investigation and sparked community resistance.
ACLU NorCal sued the Marin Sheriff’s Office in 2021 for its persistent illegal sharing with out-of-state agencies, reaching a settlement in June 2022. At the time, an Ark audit of Belvedere’s sharing agreements showed the city was also illegally sharing directly with out-of-state agencies. In response, Belvedere voluntarily agreed to revoke access, calling it an administrative oversight.
The Electronic Frontier Foundation documented 71 California police agencies continuing to break the law in 2023, prompting the attorney general’s SB 34 and 54 bulletins to all state law-enforcement agencies that year. Nonetheless, only half of those identified agencies had begun complying by the EFF and ACLU’s January 2024 letter to the attorney general.
Last June, CalMatters reported that additional Southern California agencies shared Flock data with federal immigration authorities in violation of state law, with the San Francisco Standard finding similar violations in Oakland and San Francisco.
In October, the attorney general’s office sued El Cajon police for continuing to share data with law-enforcement agencies in 27 other states, despite the guidance bulletin and multiple direct warnings.
“(Automated license-plate reader) data raises serious privacy concerns because of its ability to capture and track the movements of anyone who passes through a given area, thereby creating a database with millions of images, including individuals in vulnerable circumstances, such as undocumented individuals or people seeking reproductive care,” Bonta wrote in a Jan. 21 legal filing.
“As the Trump administration continues to target Americans’ private and sensitive data to use beyond its intended purpose, it is important that we maintain safeguards to ensure this technology is used appropriately and lawfully,” an accompanying news release said.
Reports document stalking, protest tracking, abortion surveillance
Meanwhile, headlines about Flock abuses began to surge. One Kansas police chief used Flock cameras in 2024 to track his ex-girlfriend’s movements, leading to criminal charges, while another police chief in Georgia was arrested and charged in November on allegations he used cameras to stalk and harass private citizens.
Last May, Texas deputies accessed more than 83,000 license-plate records from Texas, Washington and Illinois over a monthlong period to track a woman who had an abortion, claiming publicly that it was simply a missing-person investigation, though court records later revealed deputies logged evidence as a death investigation and consulted with prosecutors about possible charges.
The EFF found that agencies also logged hundreds of searches targeting political demonstrations between December 2024 and October 2025. Nineteen agencies conducted searches related to “protests” alone, with others searching for “kings,” related to the anti-Trump No Kings Day marches. The Tulsa, Oklahoma, Police Department’s searches targeted left-leaning protesters, such as those against deportation raids or in defense of Palestinians.
Flock spent much of 2025 denying it had any federal contracts before announcing in August it was pausing a previously undisclosed pilot program with Customs and Border Protection and Homeland Security Investigations.
The same month, U.S. Reps. Raja Krishnamoorthi, D-Illinois, and Robert Garcia, D-Long Beach, launched a formal investigation into Flock’s role in “enabling invasive surveillance practices that threaten the privacy, safety and civil liberties of women, immigrants and other vulnerable Americans.”
Lawsuit challenges warrantless searches
EFF and ACLU NorCal filed a lawsuit in November challenging San Jose police’s warrantless searches of millions of license-plate records. Between June 5, 2024, and June 17, 2025, the department and other California agencies searched the city’s database nearly 4 million times. The groups argue that location information reflecting people’s movements, even in public spaces, is protected under the Fourth Amendment and the California Constitution.
They also warn about other new Flock technologies. The firm is rolling out drones and always-on microphones to listen for human distress including screaming, raising concerns about wiretapping laws and potentially dangerous police responses to non-emergencies.
One of Flock’s primary business models involves working with police departments to encourage private entities, particularly homeowners associations, to install cameras along public roads and grant system access to police — allowing law-enforcement agencies nationwide to expand surveillance networks with no budget request, no public notification, no public hearings and no public oversight.
“It’s really concerning that government agencies are very eager and able to exploit privately run surveillance,” Cagle said. “When our local homeowners association or local community group is thinking about (automated license-plate readers), we can’t just think about them as something that we will fully control, because when the government comes and requests or demands that information, the stakes are very different.”
Cities cancel contracts over privacy concerns
Multiple cities are removing their cameras and canceling Flock contracts.
Evanston, Illinois, ordered its Flock cameras removed in August because the system violated state privacy laws by allowing U.S. Customs and Border Protection agents to access data. A month later, the city issued a cease-and-desist order when it found that Flock had illegally reinstalled the cameras. Cambridge, Massachusetts, terminated its contract in December after Flock technicians installed unauthorized cameras there as well.
In the East Bay, Richmond’s police chief shut down its Flock cameras in December after discovering its data had been made searchable nationwide, while Santa Cruz became the first California city to terminate its contract with Flock on Jan. 13, citing thousands of searches by state agencies on behalf of federal entities including ICE.
“For us, the threat to our civil liberties was greater than any benefit we could get from the flawed product,” Santa Cruz Mayor Fred Keeley told media outlets.
Prosser, Washington, deactivated all cameras Jan. 26, specifically citing “increased risk of liability” and “risk to public safety from potential misuses of the cameras,” before Mountain View’s police chief shut down its Flock cameras Feb. 2.
Nearly 30 jurisdictions nationwide have canceled or rejected Flock Safety contracts in the past year, citing privacy violations, searches by state agencies on behalf of federal entities such as ICE and Border Patrol, as well as unauthorized installations, community opposition and surveillance overreach.
Research finds mixed evidence on crime reduction
Jean provided no information on whether plate readers have reduced crime or improved clearance rates in Tiburon, but research is mixed on whether Flock cameras or other surveillance technology actually improve public safety.
A review of surveillance cameras in three cities found cameras did not consistently reduce crime, according to a 2011 study by the Urban Institute. Separate 2019 studies in Charlotte-Mecklenburg, North Carolina, and Baton Rouge, Louisiana, found no significant crime reductions and no statistically significant changes in clearance rates, or percentage of reported crimes that were resolved.
Tiburon’s previous two police chiefs frequently attributed a five-year drop in crime to the cameras after the 2010 installation, though Tiburon’s decreasing rates followed crime trends across the U.S., California and Marin throughout the period — including two of the five years that were back on par with pre-camera averages. There were also no statistically significant changes to raw clearances or clearance rates, the latter of which rose slightly for violent crimes but fell slightly for property crimes in the five years after installation. Meanwhile, Tiburon’s clearance rates for both categories in the most recent five years of data, 2020-2024, are well below pre-camera levels.
“The jury is still out on whether (automated license-plate readers) are more effective in achieving public safety goals,” researchers said in a December report in the Cambridge Journal of Evidence-Based Policing, where the authors said adoption of new technology is often driven by police and public perceptions that it could add value, rather than evidence that it does.
While Flock itself has made claims its systems help solve 10% of crime in the U.S., the self-published study was written by employees, and an independent researcher who assisted, Johnny Nhan of Texas Christian University, said the data was too incomplete for meaningful analysis and distanced himself from the company’s findings. Another Flock case study claimed its cameras reduced crime by 70% in the Southern California city of San Marino between 2019 and 2023, but an independent review by Forbes found it actually increased 5%.
Enforcement gap leaves privacy at risk
Despite thousands of documented searches for federal investigations statewide and mounting evidence of Flock abuses nationwide, California has taken minimal enforcement action against agencies that may be violating SB 34.
The Ark asked the attorney general’s office whether it had opened any investigations into the searches documented in Tiburon’s system or similar searches reported by the San Francisco Standard, CalMatters and Oakland Privacy. The office did not respond to multiple requests for comment.
Cagle said the lack of aggressive enforcement doesn’t diminish the privacy concerns created by aggregating vast amounts of location data — concerns that go beyond individual wrongdoing to the fundamental question of who controls information about people’s movements.
“Privacy is not just about having something to hide,” Cagle said. “Privacy is also about having something to protect, and that is our ability to move through communities without having our locations logged and potentially shared with people and agencies who are far away from Tiburon and don’t necessarily share Tiburon’s values and priorities.”
Reach Executive Editor Kevin Hessel at 415-435-2652.