GERMANTOWN Philadelphia homicide detectives arrested a 42-year-old Germantown man Friday in the slaying of a retired Villanova University professor who was stabbed to death in her apartment, near his home.

Jose Diaz was charged with murder and related offenses in the killing of Carol Ambruster, 69, who was stabbed multiple times in the neck and chest.

Ambruster's roommate discovered her body the night of Dec. 9 in the kitchen of her second-story apartment in the 5500 block of Wayne Avenue, the knife still in her neck.

Diaz lives in the 100 block of West Hansberry Street, blocks from where Ambruster lived.

Police did not provide a motive for the killing or say whether Ambruster knew Diaz.

Detectives said there were no signs of forced entry at her apartment, suggesting that she knew her killer or was ambushed.

The roommate, Daniel Sapon, told police that when he returned home from running errands, he found the door unlocked.

This week, police sources said, homicide detectives had interviewed a subcontractor who had done work in the apartment building and had keys to Ambruster's unit. The contractor had a criminal history, the sources said.

The sources said investigators were zeroing in on the subcontractor, whom they did not identify at the time. The sources also said the man had no wounds, which they expected Ambruster's killer to have.