Still, police were trying to determine a motive for the rampage. "Perhaps we'll never be able to answer the question that is most prevalent, and that is why," said Col. David Rohrer, chief of the Fairfax County, Va., Police Department.
"This is obviously a complex investigation with separate crime scenes and five victims. The events ... have certainly shocked and saddened us all," said Rohrer.
Investigators believe Nathan W. Cheatham shot and killed his mother in the driveway of her McLean home. He then drove 10 miles to a home in Great Falls and fired more than 50 shots that killed three other people, before turning the gun on himself.
Cheatham, 27, had been arrested on several occasions by Fairfax County police for what they described as "minor infractions."
He had been living with his mother, Sheila G. Cheatham, 53, for at least two weeks. He had also stayed with his two brothers at another location in Fairfax County. Police are hoping they can learn some indication of his demeanor, which may lead to an understanding of what led him to go on a rampage.
Police believe he broke into the second home and systematically went from room to room, fatally shooting Janina C. Price, 50, and her son Adam S. Price, 19, who both lived there, and Christopher J. Buro, 20, of Great Falls, who was visiting.
Another member of the Price family hid in the basement and was able to call for help as Cheatham opened fire. He escaped after the gunfire stopped.
Police said Cheatham was an acquaintance of the Price family. He had called them earlier in the day and was asked not to go to the home.
"There was a phone conversation between Nathan and somebody at the house," said Maj. Bob Callahan, commander of the police department's criminal investigation bureau.
Four spent clips from the 9 mm handgun were found at the house in Great Falls, an upscale suburb about 17 miles west of Washington. Cheatham also had other unused ammunition in his possession.
The body of one man was found in a bedroom closet. Another victim was found by a bed in a separate bedroom. Mrs. Price was found in the master bedroom on the second floor. Each had been shot several times.
"It appeared that they probably were still asleep or in their rooms when everything started," Callahan said.
Cheatham's body was found in the master bedroom with what police called a self-inflicted gunshot wound.
One of two black Labrador retrievers owned by the Price family was shot three times, but was treated by a veterinarian and is expected to survive.