Phil Weiser is also investigating the Mesa County Sheriff’s Office’s participation in an encrypted group chat with federal law enforcement officials.
(Mesa County Sheriff’s Office) Caroline Dias Goncalves, a University of Utah student, is seen in this screenshot from the body camera footage recorded by the Mesa County Sheriff’s Office deputy who originally pulled her over in Colorado on June 5, 2025. She was later detained by immigration officers shortly after the traffic stop.
Colorado Attorney General Phil Weiser announced Tuesday that he has filed a lawsuit against a Mesa County sheriff’s deputy whose decision last month to share information with federal immigration officials led to the arrest of a 19-year-old college student from Utah.
Weiser said it’s the first lawsuit under a Colorado law prohibiting state and local law enforcement from asking people about their immigration status. State law also prohibits officers from aiding in federal immigration enforcement outside of their criminal enforcement duties.
Caroline Dias Goncalves, a University of Utah student studying nursing, was arrested by U.S. Immigration and Customs Enforcement agents June 5 shortly after she was pulled over by Deputy Alexander Zwinck for allegedly driving too close to a semitrailer on Interstate 70 near the town of Loma.
(Caroline Dias Goncalves family photo) Caroline Dias Goncalves was held at a Colorado immigration detention center starting Thursday, June 5, 2025, according to her family. She was released after 15 days.
She told Zwinck, who is part of a group of state and federal law enforcement working on drug interdiction, during the traffic stop that she was born in Brazil. Zwinck had asked where she was born.
Dias Goncalves was released by Zwinck but then stopped and arrested by federal immigration agents a few miles down the road and taken to the immigration detention center in Aurora.
The lawsuit was filed in Mesa County. Weiser said he could seek monetary damages, but is mainly focused on preventing Zwinck from aiding in federal immigration enforcement in the future.
“Colorado law clearly directs that our limited state resources go to enforcing Colorado criminal laws and not be diverted to immigration enforcement,” Weiser said at a news conference Tuesday in Denver. “The legislature specified that such actions can undermine public trust and also deter people from accessing the services offered by state agencies and political subdivisions.”
(David Zalubowski | AP) Colorado Attorney General Phil Weiser during a news conference Wednesday, Feb. 14, 2024, in Denver.
Additionally, Weiser, a Democrat, announced Tuesday that he is opening a patterns and practices investigation into a group chat on the encrypted messaging platform Signal between members of the drug interdiction unit. It was in that chat from which the Mesa County Sheriff’s Office says information was unknowingly being passed along to ICE agents.
“We would like to reiterate that we were unaware that the communication group was used for anything other than drug interdiction efforts,” the sheriff’s office said in a written statement.
The sheriff’s office believes the chat is where federal immigration officers learned about Dias Goncalves. It has since ordered its deputies to stop participating in the chat.
Zwinck was placed on paid leave.
Weiser said Tuesday that Zwinck knew the Signal chat included federal immigration agents. The attorney general also alleged Zwinck had previously aided ICE officers in another immigration arrest and that he detained Dias Goncalves long enough to make sure ICE agents could respond.
“Deputy Zwinck kept the Driver in his patrol car for at least five minutes after informing the federal immigration officers of the driver’s location,” the lawsuit says. “Within moments of the driver leaving Deputy Zwinck’s patrol car and driving away, Deputy Zwinck messaged the federal immigration officers on the Signal chat. He relayed to them that she had left, providing them with a description of her car, her vehicle’s license plate number and the direction she was traveling.”
Dias Gonclaves was let off with a warning on the allegation that she was driving too close to a semitrailer.
“The deputy knowingly acted to assist federal immigration officers in immigration enforcement after the deputy knew that the driver wasn’t involved in any criminal activity and had no outstanding warrants,” Weiser said. “After they took her into custody, the deputy commended the immigration officers, saying, ‘nice work.’”
Dias Goncalves was held at the immigration detention center in Aurora for about two weeks after her arrest. She told The Salt Lake Tribune that her days at the facility were “the hardest of my life.” She has since been released on bond.
A relative of Dias Goncalves told The Tribune that she originally came to the United States with her parents in 2012, when she was 7. The family had a 6-month tourist visa, which they overstayed. They were afraid to return to Brazil, the relative said, after experiencing violence there, including being robbed and held as hostages by gangs several times.
Weiser said Tuesday that Dias Goncalves, through her lawyer, has asked for privacy. He declined to answer questions about her immigration status.
Neither the Mesa County Sheriff’s Office nor Zwinck responded to a request for comment submitted Tuesday to the agency.
No attorney for Zwinck was listed in the state’s court system as of Tuesday afternoon.