WOBURN (AP) — A man already serving a life sentence for a 1994 murder of a Lexington woman has pleaded guilty in the 1992 killing of another woman from the town.

Craig Conkey entered his guilty plea in Middlesex Superior Court Tuesday in the stabbing death of 31-year-old Kathleen Dempsey, who was found dead in her Lexington apartment on Aug. 23, 1992.

The 45-year-old Conkey was twice convicted of first-degree murder for killing another Lexington woman, 49-year-old Mary Lou Sale. Those convictions were both overturned by the state Supreme Judicial Court. In 2009, Conkey pleaded guilty to second-degree murder and armed robbery in Sale’s death. He was sentenced to life in prison.

Conkey was indicted in Dempsey’s death in December. He pleaded guilty Tuesday as Dempsey’s mother and father and other relatives watched.

Copyright 2012 The Associated Press.