The NYPD has demoted a lieutenant while the department’s Internal Affairs Bureau investigates accusations he slept with a snitch, The Post has learned.
Angel Thevenin allegedly began a torrid affair with a confidential informant when he was a sergeant working out of Williamsburg’s 90th Precinct in 2021, according to sources familiar with the investigation.
After an ongoing, four-month probe by Internal Affairs, Thevenin, 38, who made $183,944 last year, was knocked back down to sergeant last month.
A police spokesperson confirmed the IAB case.
Although it’s not mentioned in the NYPD’s administrative guide, sex with a CI is a no-no in law enforcement because it could compromise investigations, the sources said.
“It was clear as day that it was happening and that’s why they demoted him and knocked him back down to sergeant,” a law enforcement source familiar with the investigation said. “They had more than enough evidence.”
“He was having a relationship with somebody who was an informant,” a second source said, adding that it was a “personal sexual relationship.”
“She’s a C.I. and that means she’s doing stuff that’s not on the up and up and he’s having an affair with her?” the source said said in disgust. “I don’t get it.”
Thevenin was transferred to the Manhattan Court section — where he watches over prisoners who have come in for criminal hearings — as the investigation continues, according to the sources and public records.
“He should get arrested for official misconduct,” a longtime police officer said. “He certainly shouldn’t be around any prisoners.”
Prior to becoming a lieutenant working out of the 77th Precinct in Crown Heights, Thevenin, who is not married but is a dad, worked in the NYPD’s Narcotics Borough Brooklyn North, records show.
The allegations focus on the time he was a sergeant at the 90th Precinct, according to the source with knowledge of the internal probe. The forbidden relationship was first noted by @TheSalGreco on Twitter.
The allegations include that Thevenin violated department rules because he paid the female criminal informant for information with his own money rather than going through official channels, the sources said.
At the same time, there were “allegations of fraternization” that he was also engaging in a separate relationship with an NYPD employee, the source said.
Thevenin was promoted to lieutenant in August 2024, a month before the allegations came to light.
Thevenin was called into an IAB interview over the allegations in September 2025. He was demoted on Jan. 21.
The source added that Thevenin probably wouldn’t be fired over the trysts.
Thevenin couldn’t be reached for comment.