The girlfriend died first, shot in the head during an argument.
Next came two men in the parking lot, one of whom was shot in the back as he tried to run away.
The gunman then burst into the apartment of a disabled veteran who had urged neighbors to call 911, executing him with a shotgun.
A hail of bullets from eight Federal Way police officers took out the shooter when they found him in the parking lot, reaching for a handgun.
In about 10 minutes, five people were dead, making it the largest loss of life in a single incident in the citys 23-year history.
Detectives on Monday were still trying to piece together the chaos that unfolded about 9:35 p.m. Sunday at Pinewood Village Apartments, 33311 18th Lane S.
Preliminarily, we believe (the shooter) may have been trying to kill his witnesses, Police Chief Brian Wilson said.
Dispatchers first received a suspicious circumstances call about a man shooting a gun outside. Several other 911 calls began filtering in, and dispatchers could hear gunshots over the telephone.
Jennifer Brown, 37, who has lived in the apartment complex with her husband, two sons and a daughter for three years, went out on their porch about 9:30 p.m. to smoke a cigarette.
Thats when I heard the first round, she said. I thought it was firecrackers at first because it was an awful lot of them, she said.
A few moments later, she heard several more shots, and then her 14-year-old son saw a man in the street running from the complex.
Bullets were still flying when officers arrived and found the suspected shooter, a 28-year-old man who has not been identified, in a stairwell of the three-story complex. He was armed with a pistol-grip pump shotgun.
I could hear a police officer over a speaker say, Stop or well shoot. Get down. They said it over and over," Brown said.
She then heard another burst of gunfire.
Given the fact that he was armed, the officers fired on the subject, Chief Wilson said at a news conference, adding the shooter likely was wounded at that point.
The man dropped the gun and fled. Officers teamed up and went to search for the gunman, finding him moments later on the ground of the parking lot, about 60 feet from the stairwell.
When the man ignored verbal commands and reached for a nearby semi-automatic handgun, eight officers fired multiple rounds at him, Wilson said.
Those eight officers have been placed on paid administrative leave, which is standard procedure after a police shooting.
After killing the gunman, officers spotted the bodies of two men in the parking lot. Unsure whether there was another shooter in the complex, police used a spotlight and megaphone to urge residents to stay inside while they conducted a door-to-door search that stretched hours into the night.
The search found a 25-year-old woman and a 62-year-old man who were shot to death in their respective apartments.
Police said the woman, believed to be the shooters live-in girlfriend, was the first to die.
After shooting her, the gunman left their apartment with a large gym bag and encountered two men in the parking lot. Neighbors recall hearing an argument but couldnt tell what it was about.
The gunman shot a 46-year-old man standing near a car and then shot a 24-year-old man in the back as he tried to flee.
A 62-year-old disabled veteran noticed what was going on and came outside to investigate. Police said he ordered a neighbor to call 911 and was actively trying to gather witnesses. After the veteran sought refuge in his home, the gunman fired a shotgun blast through the front door to get inside and kill him.
The King County Medical Examiners Office has not identified the shooter or the victims. Family members identified the 24-year-old man shot in the back as Ceasar Valdovinos. They said he had been at a family barbecue next to the apartment complex before slipping off to visit a friend.
I just wish he was still here, said his mother, Sylvia Valdovinos. Thats all I wish.
She said her son moved from California in 2006 to get away from violence. He leaves behind a 1-year-old son.
I feel very numb, like this is not happening, Valdovinos said. And if the person who did this was among the deceased, Im just so happy that the police officers put him away also.
Neighbors said the man executed in his apartment after urging others to call 911 was a friendly man who walked with a cane and enjoyed sitting outside, drinking coffee and feeding the pigeons.
Residents said the shooting was out of character for the normally quiet complex.
Ive seen police activities out on the streets, but nothing to this extent, Brown said of her time at the apartments. The apartments are actually pretty safe. But after this, I definitely want to move.
Kristina Braun, 23, lives at the complex with her husband and 3-year-old daughter.
Its actually really calm, normally, said Braun, whos lived in the complex for two years. This is the first huge issue.
Police said the shooter had no criminal record but had been contacted twice by police in the past once in Federal Way and once in Seattle for domestic violence. He was not arrested for either incident. Neither involved the girlfriend killed Sunday.
The shooter had a concealed weapons permit with several firearms, including a 45-caliber handgun, registered in his name. The federal Bureau of Alcohol, Tobacco, Firearms and Explosives was helping track the history of the mans weapons, two of which were used in Sundays shooting.
Wilson said the man was listed in an internal police database for caution because he was known to carry the guns.
The city of about 89,460 residents had three homicides in 2012 and one in 2011.
Stacia Glenn: 253-597-8653 stacia.glenn@ thenewstribune.com
Staff writers Alexis Krell, Dianne McGinness and The Seattle Times contributed to this report.