Hundreds of people marched to Paterson City Hall on Tuesday to express their concern and outrage that a man who they say dedicated his life to ending violence was shot and killed by police officers last week.

Najee Seabrooks, 31, died after a four-hour police standoff on Friday. Friends say that he was suffering from a mental health crisis. Sources tell News 12 that Seabrooks was armed with knives and made threats. But details of the encounter have still not been released.

“I keep replaying Friday over and over," says Dr. Liz Chowdhury, executive director of the Paterson Healing Collective.

Seabrooks worked with the collective - a group affiliated with St. Joseph's University Medical Center. Members of that organization say they were there Friday during the standoff, but police officers would not let them help. Teddie Martinez says he was denied a chance to see Seabrooks, even though he is trained in crisis intervention.

“So how ironic is that? We’re there and I’m begging the officers, showing them text messages and things. Telling them that Najee said to me, ‘All we want to do is see your face and I’m gonna come out,’” Martinez says.

He says that the same police officers called him in recent weeks to deal with others with mental health issues.

“They brought a SWAT team in a mental health crisis. Lethal weapons in a mental health crisis. It’s clearly a mental health crisis. It was called in as an emotionally disturbed person,” Martinez says.

Part of the firestorm is Paterson's well-documented history of police officers abusing their role.

There have been changes. Police officers now wear body cameras. There has been a push to fire bad officers. Mayor Andre Sayegh says the city just got a grant that would team mental health experts up with officers. But he says it's in the planning stages.

"Today we gather to honor Najee, his smile, his energy, and to offer support to his family - our community. We demand justice and will continue Najee’s work of bringing safety and healing to Paterson,” Chowdhury says.

Activists are calling for the release of the police body camera videos from the encounter. The New Jersey Office of the Attorney General has that video and is investigating.