Levi Carl Hayes, 50, of Butler, wasn't setting out to kill his friend, Donny Schaeffer, when he stuck his knife into the 30-year-old victim's heart during a scuffle at Mr. Schaeffer's downtown Butler home. He was just trying to defend himself.

Defense attorney John Elash of Pittsburgh told a jury of seven women and five men today that Mr. Hayes was being beaten by Mr. Schaeffer and was lying beneath him when he unintentionally stabbed the man, killing him.

Assistant Butler County District Attorney Mark Lope told the jury during opening arguments that Mr. Hayes had both the opportunity and the obligation to leave Mr. Schaeffer's home.

Mr. Schaeffer died Sept. 19, 2006, within minutes of being stabbed inside his house on Virginia Avenue and the cause of death was the knife wounds to his heart, testified forensic pathologist Leon Rozin. He said the wounds were delivered with moderate force that caused no damage to surrounding bones.

Tammy Pagan, the long-time companion of Mr. Schaeffer and mother of his three children, testified that Mr. Schaeffer had asked Mr. Hayes to leave their home several times but that Mr. Hayes had refused.

She said she and a friend of the couple, Jayne Martin of Butler, had tried to pry the men apart but were unsuccessful. Ms. Martin admitted on the witness stand under cross-examination that she had struck Mr. Hayes in the face or head with her foot as she attempted to separate them.

Testimony is to continue today in Butler County Court before Judge William Shaffer.

More details in tomorrow's Pittsburgh Post-Gazette.