The 21-year-old granddaughter of an 80-year-old man stabbed to death last week was charged Monday with his murder, police said.

Patricia Diocson also was charged with possessing an instrument of crime in the slaying of Robert Girard inside his home in the 2500 block of East Lehigh Avenue.

Diocson told police that she found her grandfather's naked body around 9 p.m. last Wednesday in the kitchen of the house, where she also lived. There was a trail of blood leading to the man's second-floor bedroom. There were no signs of forced entry and nothing appeared to have been taken, police said.

Diocson claimed her grandfather was abusive to her, police said.

During the homicide investigation, police towed away a white commercial van that had been parked in front of Girard's house for about a month. A man who was living in the van was charged with possession of heroin, but was not believed to have been involved in Girard's death, police said.