The tragic incident began at 1:21 a.m. when an emergency 911 call came in to fire dispatchers from a duplex in the 800 block of 141st Place SE in Bellevue.
Fire crews arrived about six minutes later and found the boy's mother crying for help outside the building. She and another woman had made it out of the building safely, but she told firefighters her little boy was still inside.
"They had to fight their way through the first floor. There was fire on the first floor to make it to the second floor, where they found the boy," says Lt. Eric Keenan, Bellevue Fire Department spokesman.
Firefighters got the boy outside and worked on him, then rushed him to Harborview Medical Center, but he died.
The boy's 23-year-old mother and the other woman are still at Harborview. They are unhurt but want to be with the little boy.
Detectives are waiting for a search warrant to get inside the building so they can investigate the cause of the fire.