Around 11 a.m. on July 19, Sgt. Scott Costella was patrolling a dirt road in Berkshire, a small town in Northern Vermont along the Canadian border, when a car without a front license plate drove past him.
Costella, a deputy at the Chittenden County Sheriff’s Department, swung around and a few minutes later pulled the vehicle over, according to cruiser dash camera video published this week. After speaking to the driver and passenger, Costella went back to his cruiser, got his phone, and texted two U.S. Border Patrol agents.
“Potato hill rd on stop. Need one of you,” Costella said, according to a screen shot of the text messages.
The video shows two agents responding to the scene and removing the passenger, Genri “Alex” Jimenez, from the car. Jimenez, a 22-year-old Mexican man, was handcuffed, taken to the agents’ car, and driven away. He was detained for nearly three weeks by Immigration and Customs Enforcement before being deported to Mexico, advocacy group Migrant Justice said in a press release.
The incident came to light this week after Migrant Justice released public records showing the traffic stop and Jimenez’s detention. The group says Costella’s actions violated a state policy meant to bar Vermont cops from aiding in federal immigration enforcement.
But what was Costella doing miles away from Chittenden County, patrolling backroads in Franklin County near the Canadian border?
The answer: Operation Stonegarden, a federal program run by the U.S. Department of Homeland Security that gives funding to local law enforcement agencies in exchange for help policing the border.
The post-9/11 program has funneled hundreds of thousands of dollars to Vermont police departments, primarily rural ones along the northern border. The grant funding can be used to buy equipment, like boats, trucks and ATVs, and pays officers overtime while they patrol the border.
Chittenden County Sheriff Dan Gamelin confirmed to Vermont Public on Thursday afternoon that Costella was working a Stonegarden shift on the day of the traffic stop. Seven Days first reported that Costella was working on the federal detail during the incident.
State law enforcement officials have said for years that Operation Stonegarden’s primary focus is to prevent criminal activity near the border, like drug smuggling and human trafficking — not civil immigration enforcement. But critics say Costella’s traffic stop shows how easily the program blurs lines between those enforcement activities.
“This is exactly the sort of thing that we've said would happen through local cops' participation in this program, and nobody should be surprised when it finally happens,” said Will Lambek, with Migrant Justice, in an interview.
As of 2025, six Vermont police agencies were participating in the program, including the Chittenden County Sheriff’s Department, Swanton Village Police, and the Essex County Sheriff’s Department, according to the Boston Globe.
The Chittenden County Sheriff’s Department had received more than $218,000 through Operation Stonegarden in 2025, which the Globe reported was the most of any of the participating departments in Vermont that year.
A spokesperson for U.S. Customs and Border Protection didn’t answer specific questions about how Stonegarden works in Vermont or how many detentions stem from work done by local police.
Instead, the spokesperson provided a one-sentence written statement that said the program “provides funding to enhance cooperation and coordination among state, local, tribal, territorial, and federal law enforcement agencies to jointly enhance security along the United States land and water borders.”
Four or five Chittenden deputies used to work Stonegarden shifts “religiously,” Gamelin said in an interview, though he noted the department has scaled back its time on Stonegarden as its workload in Chittenden County has increased.
“We have to follow the fair, impartial policing policy while we're working up there,” Gamelin said.
Vermont’s Fair and Impartial Policing Policy limits information sharing between local law enforcement and federal immigration authorities, including information about a person’s location and vehicle information. The policy does have exceptions if there is a risk to public safety or officer safety.
Costella, in a report about the traffic stop, wrote that he asked Border Patrol agents to respond as “officer safety backup,” though records show he added the phrase “officer safety” after an internal legal review of his report.
Gamelin has asked the state panel that regulates law enforcement credentials to review the incident, and he’s brought in an outside investigator to conduct an internal review. Gamelin declined to comment further, saying that it’s a personnel issue.
“I take that motor vehicle stop, the incident that happened up there, very seriously,” Gamelin said. “It is troubling for me — period.”
This isn’t the first time the Chittenden County Sheriff’s Department has been accused of aiding federal immigration authorities. In 2019, a deputy called Border Patrol to a traffic stop that resulted in the detention and deportation of a 21-year-old farmworker, though it’s not clear if that deputy was working on a Stonegarden shift. The department paid $25,000 to settle a discrimination complaint filed by a man who was deported.
For now, Gamelin said he’s suspended his department’s participation in Operation Stonegarden. He told Vermont Public he’s not aware of any other incidents where deputies on a Stonegarden shift have called Border Patrol during a civil traffic stop.
Vermont’s top law enforcement official, Attorney General Charity Clark, has previously said she doesn’t see a conflict between Stonegarden and the state’s Fair and Impartial Policing Policy.
“Stonegarden does not require Vermont agencies to perform any of that off-limits civil immigration enforcement work,” Clark told the Boston Globe last year.
In a written statement Friday, Clark reiterated Stonegarden’s focus is on criminal law enforcement, which is permitted under the Fair and Impartial Policing Policy. She also noted her office sued to prevent the Trump administration from imposing civil immigration enforcement conditions in grant programs like Stonegarden.
Clark also said that police shouldn’t be involved in civil immigration enforcement, “be it under Operation Stonegarden or otherwise.”
“They would be running afoul of the FIP Policy and would be subject to discipline or other consequences from the Criminal Justice Council,” Clark said in the written statement.
But Lia Ernst, legal director at the American Civil Liberties Union of Vermont, said there are still Stonegarden program requirements that run afoul of the Fair and Impartial Policing Policy.
The 2025 Vermont Operation Stonegarden guidelines require grant recipients to "honor requests for cooperation," like sharing of information and requests for short-term detentions of people — which are things that Fair and Impartial Policing Policy prohibits, Ernst said.
“Vermonters have made clear time and again … that they do not want Vermont law enforcement aiding and abetting the work of Immigration and Customs Enforcement,” Ernst said. “And Stonegarden is exactly that.”
