Officer Katherine Shea, a police spokeswoman, said officers responded at 1:34 p.m. and spoke to witnesses who identified the suspect, whom she declined to name.

“For a moment there it was pretty frightening,” said Darek Barcikowski, Walczak’s campaign manager.

Violence erupted Sunday at a rally organized to introduce mayoral candidate Bill Walczak’s public safety plan, when a man ran into the crowd and struck several people.

Police were able to quickly apprehend the suspect, and he was transported to Boston Medical Center for a psychiatric evaluation, Shea said.

Barcikowski said residents told the campaign that the suspect was known around the area and is mentally ill.


Barcikowski said the melee began after Walczak introduced his plan, which includes increasing police diversity, taking a public-health approach to domestic violence, and improving re-entry services for offenders who have served their time.

As a worker packed sound equipment into his car, a man walking on Washington Street near Talbot Avenue began chasing and yelling at the worker. When campaign volunteers and supporters tried to intercede, the man became violent.

Barcikowski said the man struck “at least five people” of about 50 gathered for the rally and knocked over a speaker, damaging it. The man then grabbed a woman by the hair and threatened to hold her hostage, Barcikowski said.

“I think everybody got a little scared because we weren’t sure what he was capable of, or whether or not he had a weapon,” he said.

He said some people freed the woman from man’s grasp and chased him away. No one was badly injured.

Jeremy C. Fox can be reached at jeremy.fox@globe.com. Follow him on Twitter @jeremycfox.