MUSKEGON, Mich. (AP) — A man killed by other inmates at a western Michigan prison had been locked up since 2017 for convictions in Chippewa County in the Upper Peninsula, records show.

The Corrections Department identified him as Joshua Stead.

READ MORE: 5-Year-Old Injured In Eastpointe Accidental Shooting; Gun Safety Instructor Says Lock Up Your Guns

Stead, 40, was killed Saturday when two men at the Brooks Prison in Muskegon attacked him with a weapon and walked out of his cell less than a minute later, the Corrections Department said.

“At the time of the attack, prisoners were free to move about, go to the dayroom, the yard, et cetera. Some stay in the cells and close the door,” spokesman Chris Gautz said Tuesday. “In this case, with this cell, the door was open and Stead was inside the cell.”

READ MORE: Ballot Initiative To Strike Detroit's Adult-Use Ordinance Rejected, Opponents Continue To Fight

He said state police were investigating. The attackers have been transferred to a maximum-security prison.

In 2017, Stead pleaded no contest to assault and fleeing from a police officer. He had previous convictions in Genesee, Antrim, and Grand Traverse counties, online records show.

MORE NEWS: 5-Year-Old Accidentally Shoots Self In Foot At Eastpointe Home

© 2021 Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.