The gunman's wife of six years, Lana Carlson, 49, and her sons, Quinn and Tory Carlson, who were 16 and 18, respectively, were shot to death alongside a fourth person who was not identified.
Their bodies were found Friday in a chicken coop on the remote, wooded property near Belfair, on the Kitsap Peninsula southwest of Seattle.
Tory Carlson was studying culinary arts at Olympic College, according to King.
He and his brother Quinn were both adopted from Russia by their mother Lana, Komo News reported.
Jack Pigott, who lives down the road, said he heard gunshots Thursday night.
It was common for the family to do shooting practice, Pigott said. That's what he assumed Thursday's gunfire was.
'I was getting a load of wood into the house, and I hear some gunshots,' he said. 'Four or five, a pause and then another round.'
The Mason County Sheriff's Office on Saturday released a timeline of the standoff, which began after David Campbell called a sheriff's office supervisor Friday morning to say he had done something bad and was suicidal.
A small number of deputies initially responded, speaking with Campbell, 51, by phone and setting up a perimeter to keep him on the property until a SWAT team could arrive.
Over three and a half hours, trained negotiators tried to persuade Campbell to surrender, but 'it became evident that the suspect was not going to leave the residence voluntarily,' the sheriff's office said.
Deputies could see him pacing inside, often holding a handgun to his head.
When they deployed tear gas in the house, Campbell came outside with a gun in his hand and yelled at police.
He then returned indoors before coming out once more, putting the gun to his temple and firing as the police watched.
Authorities said she wasn't shot, but they used a military-surplus armored vehicle to pick her up and bring her safely past the home so she could be evaluated by medical personnel.
'Apparently she's OK,' Chief Deputy Ryan Spurling said. 'I don't know if this is a daughter, or stepdaughter, or what the relationship is, but she escaped from the house.'
Campbell and Carlson were married in November 2009, King County records show.
The wife had two teenage sons who were adopted from Russia during a previous marriage, Pigott said, as well as a daughter who was adopted from China.
Her previous husband died of cancer, he said.
