Twin Cities activist Andrew Henderson claims Sgt. Jeff Rothecker is the man behind a Facebook account that directed people to run over protesters at two Monday afternoon rallies slated to converge on the Lake Street-Marshall Avenue Bridge. Commenting on a Pioneer Press article about the demonstration, Facebook user JM Roth called protesters “idiots” and provided instructions for drivers on how to hit them with impunity. Here’s the comment in its entirety:

“Run them over. Keep traffic flowing and don’t slow down for any of these idiots who try and block the street. Here is the deal, you continue to drive and if you hit someone make sure you call 911 to report the accident and meet the cops a block or two away and you can justify stopping further away because you feared for your safety since in the past people in this group has shown [sic] a propensity towards violence. Since they are trying to block the street and/or cross where there is no crossing you should not be charged with anything. Now, these idiots could try and sue you in civil court, but remember that it will be jury trial and so most likely it will come out in your favor.”

The comment and the JM Roth account have since been deleted. But Henderson, of anti-police brutality group Minnesota Cop Block, says JM Roth comments regularly on the group’s Facebook page. Usually the barbs call their readers “idiots,” say they couldn’t handle being cops, or hurl other insults. But this was the first time he saw JM Roth preach violence.

“When I saw that coming from a police officer, a person who is sworn to serve and protect people, it really struck a chord with me,” Henderson says.

Henderson met with St. Paul police on Sunday to formally file a complaint. During the meeting Henderson presented them with a disc containing other screen shots and information allegedly proving that Rothecker is JM Roth. Henderson claims he dug up Rothecker’s marriage license and took screen shots of his wife’s Facebook page listing JM Roth as her husband.

In one screen shot, another Facebook user appears to call out JM Roth as Jeff Rothecker. During the September 2015 exchange, JM Roth replies “Yup, you don’t see me denying do you?”

For months, activist Michelle Gross says JM Roth trolled various police accountability pages she runs, including Communities United Against Police Brutality. JM Roth often posted up to two or three racist comments a day on her pages, Gross says. After Jamar Clark was killed by Minneapolis police in November, Gross says JM Roth “went crazy” upping the vitriol and frequency of the posts, suggesting people killed by police deserved to die. Two weeks ago she blocked him.

“He’s supposed to be a leader of other police officers,” Gross says of Rothecker. “For him to be advocating running people over and how to get away with it, I think he needs to be disciplined.”

Rothecker did not immediately respond to a request for comment. Citing state law, St. Paul police say they can’t comment on the specifics, but they are investigating the post. In a statement, the department pledges that if the comment came from one of their own, disciplinary action will be taken.

“The statement is offensive, disappointing, concerning and does not reflect in any way — or align with — the views, values and practices of the Saint Paul Police Department,” the statement says.

Mayor Chris Coleman also says in a statement that he’s “outraged and disgusted” by the post, and that if the claims are true punitive action will be taken.

Rothecker has been with the St. Paul Police Department for 22 years and is a vice president of the Minnesota Fraternal Order of Police. According to his bio, he investigates elder abuse complaints.