The Michigan man who in 2022 was convicted of the 1975 murder of his wife in Door County has died.Richard G. Pierce passed away last month at Dodge Correctional Institution, according to the Wisconsin Department of Corrections.Pierce was charged with killing his wife, Carol Jean Pierce, in 2018.The couple was married in 1966. Pierce was a sailor for the U.S. Coast guard based in Sturgeon Bay when Carol Jean disappeared in 1975.In April 2022, Pierce was found guilty of first-degree murder and disinterment of the dead. He was sentenced to life in prison on a count of first-degree murder.The charges were largely based on witness testimony; several witnesses said Pierce had seemed unhappy in his marriage to Carol Jean.One neighbor said Carol Jean told her at least three times she thought Richard was going to kill her and she wanted to go somewhere no one would find her.Another said Carol Jean had told her Pierce beat her the night before and her face had been bruised.At the time, Pierce's former shipmates told authorities Carol Jean didn't trust Pierce. One shipmate recalled how the ship captain's wife had died and Pierce commented: "That was a pretty good deal. (The captain) got rid of his wife."Carol Jean Pierce's body has never been found. NBC 26 reached out to Richard G. Pierce's brother but he declined an interview.