Collins lived alone in a Southfield apartment.
Neighbor Drema Sanders, who lives in the same building, said she had just seen him at the mailboxes last Friday. Sanders said Collins had some kind of growth on the left side of his face that covered part of his mouth.
"He was always respectful," said Sanders, 59. "He would nod, because he couldn't really talk."
Angelica Mercado, the leasing manager for the apartment building, said Collins had lived there for about 1½ years. She described him as very active.
"I would never hear a complaint from him or from his neighbors about him," she said.
Hawkins did not reveal the name of the sergeant who was wounded in the shoulder but said he was in stable condition Monday at a hospital. He said at least five officers were involved in the shooting, but he would not say how many fired their weapons.
"We train these officers to deal with situations like this; to deal with the unusual, to deal with the unpredictable," Hawkins said. "And this certainly qualified. They performed exactly like they were trained."
Surveillance video that captured Sunday's shooting is part of the investigation and was not released Monday.
The shooting was the second at a Detroit-area police station in less than two years.
Four Detroit police officers were shot and wounded Jan. 23, 2011, by 38-year-old Lamar Moore at a west side station. Surveillance video showed Moore walking into the precinct and opening fire on the officers. He was shot to death in the exchange of gunfire.
Associated Press researcher Monika Mathur in New York contributed to this report.