Officials decided to revisit the case of Betty Schirmer's death in 2010 after a man committed suicide inside Arthur Schirmer's church office.
The man's suicide was prompted by the discovery that his wife had been having an affair with Schirmer, police said.
Schirmer admitted on the stand that he and his second wife had not been intimate in a number of years. Schirmer said Betty Schirmer had been through menopause and wasn't interested in sex. He also admitted he viewed pornography on his home computer.
The Associated Press contributed to this report.