A father apparently shot to death five of his children, aged seven to 16, at their mobile home and then killed himself near a casino, police said. Ed Troyer, a spokesman for the sheriff, called it a domestic violence situation and a murder-suicide. "We believe they all died of gunshot wounds," Troyer said Saturday. Police found the father's body early Saturday in his still-running car near the Muckleshoot Casino in Auburn, about 30 miles south of Seattle. He had apparently killed himself with a rifle, although no note was left in the car, Auburn Police Sgt. Scott Near said. Later in the day, deputies checked the mobile home, which is about 20 miles southeast of the casino, and found four of the children dead in their beds and the fifth in the bathroom. Neighbors in the Deer Run mobile home park, a neat, well-kept community nestled among towering evergreens, were shocked and weeping at the news. "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." The mother of the victims was not at home, Troyer said. Deputies were called to the mobile home after a relative stopped by and saw a child lying motionless on a bed through a window, but couldn't get anyone to answer the door. He said investigators believe the husband and wife were not estranged. Pierce County Sheriff Paul Pastor described the crime as a "horrible thing." "This was not a tragedy. It was a rotten murder," 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." Ryan Peden, a classmate of the eldest daughter, 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. Authorities did not release the names of the family, but Troyer identified the dead children as four girls and a 7-year-old boy. Another neighbor, Dale Lund, told The Seattle Times the seven-year-old boy who was killed played at times with his grandson and the boys shared the same school bus stop and attended the same elementary school together. He said the dead boy played in his own yard most of the time. "They pretty much kept to themselves over there," Lund said. Dozens of investigators were on the scene trying to reconstruct the crime and discover a motive.