Updated 8 p.m. with method of attempted suicide, additional background.

JACKSON, MI -- Eric John Knysz, the convicted murderer of Michigan State Police Trooper Paul K. Butterfield II, has attempted suicide and is "on a ventilator at this time," First Lt. Chris McIntire of the Michigan State Police Rockford Post has confirmed.

Knysz was at the Michigan Department of Corrections’ Charles Egeler Reception and Guidance Center in Jackson when he attempted suicide.

Michigan Department of Corrections spokesman Russ Marlan later confirmed that Knysz tried to hang himself with a bed sheet Monday afternoon, April 14. Knysz was still alive as of 7:35 p.m. Monday at a Jackson hospital, Marlan said in an email.

Knysz was sentenced Tuesday, April 8, to life in prison without possibility of parole for first-degree murder of a peace officer.

A Mason County jury Feb. 25 convicted him of that charge as well as a felony firearm count, carrying a concealed weapon and unlawful driving away of an automobile, habitual second.

Knysz shot Butterfield in the head at a traffic stop around 6:20 p.m. Sept. 9, 2013, on a rural road in Mason County.

According to testimony at his trial, his motive was fear of going to jail or prison because he was driving on a suspended license and had guns concealed in the pickup truck he was driving.

John S. Hausman covers courts, prisons, the environment and local government for MLive/Muskegon Chronicle. Email him at jhausman@mlive.com and follow him on Twitter.