The man involved in the shooting with police is Jeffery D. Hamlet, 30, the father of the 3-year-old, authorities said.
The suspect in the child's death is William Henry Johnson III, 28, the boyfriend of the 3-year-old's mother.
Jamari Lim-Hamlet had just celebrated his third birthday.
“Playful, very easygoing, such an easy kid,” said Tara Edwards, a neighbor.
The boy's mom, Jackie, showed KIRO-TV photos of her son. They showed a boy full of smiles who loved Spider-Man.
Normandy Park police said the boy was killed Saturday evening and believe that his mother's boyfriend beat him to death.
“Very disgusting,” said Fred Aigbe, also a neighbor.
“It’s just horrible. He's just such easy kid. And to know he was going through that, with no one really there to be able to help him, it's giving me chills right now,” Edwards said.
The family's neighbors are so shaken up, they didn't want to show their faces on camera.
“Our kids play together,” Edwards said. “And literally two hours after he left, this is what went on."
Johnson waived his appearance in court Tuesday, but a judge announced charges that will likely come Wednesday.
“This court finds probable cause of murder two,” the judge said.
First responders first came to the home in Normandy Park on a "CPR in progress" call. When they arrived, they found bruising and other signs of trauma on Jamari’s body and notified police, authorities said.
“We don't believe there's anyone outstanding as far as the responsibility for what we believe is a crime that took place,” said Chief Dan Yourkoski, with the Normandy Park Police Department.
Police said that when Hamlet, the boy’s father, found out that Jamari was dead, he sent threatening text messages to the boy's mom.
The messages were so threatening, police were concerned he would drive by and shoot up the house where Jamari died, which was still a crime scene at the time, authorities said.
The development led police to shut down First Avenue South for hours from 3 a.m. to 7 a.m. Sunday.
On Monday afternoon, Normandy Park police were investigating the felony harassment case and tried to arrest Hamlet about a quarter-mile away from the home, at First Avenue South and 160th in Burien.
The King County Sheriff’s Office said Hamlet ran and got stuck near a fence. He allegedly opened fire at Normandy police, and officers fired back.
One of the bullets grazed Hamlet’s head, police said.
Hamlet then ran across First Avenue South again to the Arby’s, where he pointed his gun at two people in a car in the drive-thru lane and carjacked their car, authorities said.
He tried to flee, the Sheriff's Office said, then hit a median and got stuck. Then police arrested Hamlet.
Now two men are behind bars – one on suspicion of murder, the other for what police say he did after he found out.
“Sometimes you’ve got to think before you do. No matter how much heartbreak it is, you’ve still got to control yourself and figure it's about your other kids, too,” Aigbe said.
Hamlet will be in court Friday to face charges related to the shootout and carjacking.
Friends of the family of the toddler have started a GoFundMe to create a memorial for the boy.
There also will be a fundraiser and memorial picnic Sunday at Golden Gardens Park in Seattle from 3 to 7 p.m.
Cox Media Group