The three people killed inside a Tioga home over the weekend — including the 92-year-old homeowner — were slain during a robbery, police said Monday, for the first time stating a motive for the crimes.

Homicide Capt. John Ryan said Warren Harrison, well-known in his neighborhood for his love of gardening, was found beaten to death Saturday in the basement of his home on the 1900 block of Venango Street. Harrison's companion, Khadijah Abdullah, 60, was found dead from stab wounds in a second-floor bedroom, Ryan said, while Abdullah's brother, Earl Cottle, 57, was found dead from blunt-force trauma in the basement.

The house had been ransacked, Ryan said, and all three victims were covered in blankets, an apparent attempt to conceal their bodies.

"It's a terrible tragedy that happened on Venango Street," he said at a news conference at Police Headquarters.

The incident that shocked neighbors over the weekend. Ryan said detectives were seeking answers to a variety of questions, and  declined to identify potential suspects or say what had been stolen. No arrests were made.

Ryan said Harrison's daughter, who lived at the home with her father and Abdullah, had been out of town before she came home Saturday evening. Discovering the gruesome scene, she called police, who responded around 7:30 p.m. All three victims were declared dead at the scene.

Police believe the killings occurred early Saturday, Ryan said, adding that it appeared the two men struggled with their attackers before their bodies were moved to the basement.

Ryan said  Cottle must have been visiting the house. Harrison often had boarders, Ryan said, and police believe that whoever committed the robbery knew the residents.

"We don't believe it was committed by a stranger," Ryan said. "We believe it was committed by someone that was known to them, that was let inside the house."

Ida M. Harrison, 79, who said she married Harrison in 1963 and remained close with him after they separated in the 1980s, said Monday that the crime was "senseless," adding: "I just hope the police capture who did this to him, because it wasn't worth what they broke in the house to do to him."

Warren Harrison had owned the home for nearly 30 years, according to property records. He grew potatoes, beans, corn, and tomatoes at a nearby community garden before it was redeveloped with homes, according to a 2010 Inquirer story. Neighbors said this weekend that in recent years, he had harvested collard greens in his front yard.

Ryan said a $60,000 reward is offered for information that leads to an arrest and conviction in this case.