The detective in question, Stephen LeBert of the Medford, Massachusetts, Police Department, is now on administrative leave pending an investigation after the release of the video
, which contains explicit language.
"I'll put a hole right through your head," said LeBert repeatedly, often swearing at the driver as well.
The incident happened Sunday night in Medford, a few miles north of downtown Boston. The driver admits he took a wrong turn at a traffic circle, and LeBert pulled him over.
The driver, a 25-year-old man, who would only call himself "Michael," said he did not realize LeBert was a member of the police when the detective first confronted him. LeBert was off duty and wearing camouflage shorts and a tank top at the time of the incident. LeBert does appear to show his badge at one point, but it's not clearly visible on the video.
"He wasn't driving a police vehicle. There were no lights. There was nothing," said the driver in an interview with CNN affiliate WHDH
After LeBert stood in the street yelling, the driver pulled in behind LeBert's truck. The detective continued yelling.
"You're lucky I'm a cop because I'd be beating the f***ing p*** out of you right now," said LeBert.
The driver told LeBert about the dashcam recording their interaction. LeBert called in on-duty police officers. The video showed the officers speak calmly with the driver and LeBert before advising the driver he was free to leave. LeBert continued to berate the driver, who LeBert said almost hit his car head-on at the traffic circle, and says he almost hit him, too.
"It was definitly nerve-wracking -- when someone is like, hey, I'm going to shoot you," Michael told WBZ
The driver's dashcam recorded the entire interaction with the detective and the video was posted later that day. It's not known if video exists of the traffic incident that led to the stop. Medford Police Chief Leo Sacco said his department had not received video.
Sunday's incident is not the first time LeBert has drawn scrutiny from the public and the police department, Sacco said.
In 2012, a different video
showed LeBert in a police uniform at the scene of an incident where a man is being questioned about drug activity. He's smiling and attempting to smear the lens of a camera. In the video, LeBert talks with the man recording him, and asks if he is the brother of the man the police are dealing with.
"What they should do is take him up to the railroad tracks and tell him to lay down," said LeBert in the video.
Sacco said that after the video of the 2012 incident emerged, LeBert was counseled and given a verbal reprimand.
LeBert has been a police officer for 30 years, and a detective since 2007, according to Sacco. "He is a very effective officer, he does good work. Just two weeks ago he solved seven housebreaks."
"If you work hard you do step on people's toes, which generates complaints," Sacco said.
The Medford Police Department has said it has begun investigating the latest incident.
"That's not proper behavior, but we only know about it when people tell us," Sacco told CNN affiliate WFXT
. "And unfortunately, we had to get up this morning to see it on a YouTube video."
CNN was unable to reach LeBert for comment.