NEW YORK (CBSNewYork) — A mother is suing the City of New York, alleging that an officer was not prepared to deal with mentally disturbed people and wrongfully killed her son.

As WCBS 880’s Mike Sugerman reported, police said Dwayne Jeune was moving toward an officer with a knife, and after he did not respond to a Taser, he was shot four times by Officer Miguel Gonzalez.

“We miss our son. It’s hard. It’s hard to reflect on what happened to him,” said Jeune’s father, Vibrant.

It was around 12:30 p.m. Monday, July 31, when Jeune’s mother called 911 reporting that her son was behaving erratically in their home in East Flatbush, Brooklyn.

Investigators say four officers responded to the call and Jeune’s mother let them into the apartment where, within seconds, police say Jeune was charging at them with a 14-inch knife.

At first, detectives said the officers tried to stop Jeune with a Taser, hitting him twice. Police said Jeune fought through the Taser shot and went on moving forward, and an officer then fired multiple shots, striking Jeune in the chest.

Jeune had a history of mental illness, and activists noted that this was one of a number of police shootings dealing with the mentally ill.

“We work with five families who have lost loved ones in the last few years to police violence for mentally ill and this has to stop,” said Hawk Newsome of Black Lives Matter.

Police had no comment on the lawsuit filed by Jeune’s family, which requests $20 million in damages.