GRAHAM, Washington (AP) – Authorities were still puzzling yesterday over what might have driven a man to slaughter his five children inside their home in Washington state.

The authorities are trying to figure what might have driven 34-year-old James Harrison to slaughter his family and then took his own life.

The neighbourhood was quieter yesterday morning. The dozens of investigators who swarmed the scene after the bodies were discovered Saturday had gone.

A few people drove slowly past the neatly kept mobile home, in a quiet park nestled among towering evergreens. The home’s front yard was still littered with toys: bicycles, a swing set, a trampoline and a basketball hoop.

“How could something like this happen?” asked Mary Ripplinger, whose kids were playmates of the slain children. “Everyone’s asking: Why did he do it? It’s not right.”

A relative visiting the family’s doublewide trailer at the Deer Run mobile home park yesterday could not get anyone to answer the door but looked through a window and glimpsed a child lying motionless on a bed.

Pierce County deputies called to the home 15 miles (24 kilometres) south-east of Tacoma found four children murdered in their beds and the fifth slain in the bathroom. The four girls and the youngest child, a seven-year-old boy, apparently had been shot.

“This was not a tragedy. It was a rotten murder,” Pierce County Sheriff Paul Pastor said. “This appears to be the terrible work of the biological father. If that doesn’t break your heart, I don’t know what does.”

Earlier Saturday, police found Harrison dead in his still-running car near the Muckleshoot Casino in Auburn, about 18 miles (29 kilometres) north of Graham and 30 miles (48 kilometres) south of Seattle.

He had apparently killed himself with a rifle, Auburn Police Sergeant Scott Near said. No note was left in the car.

The mother’s aunt, Penny Flansburg, identified the couple as Angela and James Harrison and the children as Maxine, Samantha, Heather, Jamie and James. Harrison worked as a diesel mechanic and his wife works at Wal-Mart, Flansburg said.

She was at a loss to explain the crime.

“They were pleasant together,” Flansburg said. “We can’t even figure out why.”

Ryan Peden, a classmate of the eldest daughter, who was 16, said she told him Friday night that her parents had gotten into a fight and her mother had left. The father followed the mother and tried to get her to return, said Peden, 16.

Carolyn and Raymond Bader, former neighbours of the family, told The Seattle Times they often heard the father yelling at the children. The Baders said they called the sheriff’s department and Child Protective Services several times with their concerns.

“We did all we could to help these kids,” Raymond Bader said. “We tried to protect these kids. We did what we could.”