The Special Investigations Unit has cleared police after an incident following a knife attack at a gun store.

On March 23, a 19-year-old man entered Select Shooting Supplies in Cambridge. After a short verbal exchange, police say the man attacked the store owner, Dean Carr, with a knife.

Police tried to arrest him in the store, but he broke free and ran away.

When more officers arrived, the man was found in a vacant lot nearby with cuts to his neck and wrists.

“It is evident on the SIU’s preliminary inquiries into the circumstance surrounding the man’s injuries, that they were intentionally self-inflicted in a moment of acute mental distress,” says Interim Director Joseph Martino in a news release.

Carr said at the time that the incident was a random act of violence.

“He could have targeted anyone, anywhere. He just happened to walk into our store,” he says in part in a written statement.

He says that, though his injuries were severe, he believes his wounds will heal.