GREENSBURG, Pa.—The attorneys for a western Pennsylvania man accused of killing his mother, sister and elderly aunt three years ago want a judge to bar prosecutors from using statements he made at an upcoming murder trial.

The Pittsburgh Tribune-Review ( http://bit.ly/Ja6fr6) reports a defense psychiatrist testified Monday that Kevin Murphy had suffered a panic attack and taken Valium before talking to police about the killings inside a Westmoreland County auto repair shop in April 2009.

Investigators say Murphy told them he brought a handgun to the garage earlier in the day but denied killing his mother, 69-year-old Doris Murphy, his 43-year-old sister Kris Murphy and his aunt, 81-year-old Edith Tietge.

Prosecutors say Kevin Murphy killed them because they disapproved of his relationship with a married woman. His trial is scheduled for October.