NEW : Shooting in Federal Way , Washington , began with domestic dispute , police say . NEW : Police are investigating a shooting at the home of an FBI agent who was shot and killed by his wife while they were arguing over custody of their children. NEW : Ties between gunman , three of the victims are unclear , police chief says . Shots were still being fired when officers arrived , police spokeswoman says .
NEW : Shooting in Federal Way , Washington , began with domestic dispute , police say . NEW : Gunman killed four people before being fatally shot by police . NEW : Ties between gunman , three of the victims are unclear , police chief says . Shots were still being fired when officers arrived , police spokeswoman says .