Mayor Marty Walsh says he’s unhappy with the way the Boston Police Department handled the arrest of a local construction worker, in light of a a new lawsuit filed by the U.S. Department of Labor. The lawsuit alleges the Tara Construction company unfairly retaliated against an employee, Jose Martin Paz Flores, who is not a legal U.S. resident, after Paz filed for worker’s compensation.

According to the lawsuit, which was originally reported by WBUR's Shannon Dooling, ownership at the construction company contacted two Boston Police detectives, who in turn contacted agents from U.S. Immigration and Customs Enforcement (ICE), and arranged for Paz to be arrested in 2017.

During his monthly "Ask The Mayor" segment on Boston Public Radio, Walsh told WGBH News’ Jim Braude the BPD mishandled the case.

"I didn't like the way this case came down,” Walsh said.

When Braude pressed if that meant Walsh was “unhappy with the way the Boston Police handled it,” Walsh said, “I'm unhappy with the particular way this whole case got handled."

The suit claims Paz was arrested with his then two-year-old son in the car with him, by a “joint ICE/Boston Police Department task force.”

“It seems like an employer here was was trying to kind of get back an employee,” Walsh said. “The employer actually made the calls with the assistance I guess. And it's unclear about what role detectives played in this particular case, but I want to be very clear on [this] when I talk about immigrants in Boston: We we shouldn't be criminalizing immigrants.”

The ACLU of Massachusetts has filed a public records request to gain more information on the case. Walsh said he’s working with the U.S. Labor Department, the Boston Police (including several calls with BPD Commissioner William Gross) and The Boston Globe's Yvonne Abraham.

“It's still being unpacked as we talk, still trying to get to the bottom of exactly what happened in this particular case,” Walsh said. “The facts that I have in front of me right now are that this person had a workers comp claim and used a fake name. I don't know if the company is upset about it, but in my opinion that does not warrant having the federal government use resources to come in and grab somebody.”

This article has been updated to reflect that WBUR first broke the story, not The Boston Globe.