Detectives continued an investigation this week into the death of a 4-year-old Enumclaw boy, a death that was deemed “suspicious” by both hospital and law enforcement staff.

The boy died Thursday at Mary Bridge Children’s Hospital after spending several days at the Tacoma facility.

The story unfolded Jan. 1 when the boy’s mother left her son in the care of her boyfriend of three months, according to a King County Sheriff’s Office spokesman. The mother had to go to work and the boyfriend was caring for the youngster at an Enumclaw apartment.

The boyfriend called the mother that night, reporting the boy was sick. He took the child to his mother’s house; authorities did not give the location of that residence. When the mother got off work, she and her boyfriend returned to her Enumclaw apartment, with the child, according to the KCSO source.

After staying up with the sick child, the couple decided to take the boy to Mary Bridge. When the child went unconscious in the car, the two diverted to Valley Medical Center in Renton. After examining the child, Valley Medical staff ordered the child airlifted to Mary Bridge. Believing the child’s injuries were suspicious, Valley Medical personnel notified the King County Sheriff’s Office.

Contacted Friday afternoon, KCSO spokesman John Urquhart said the department would not take further action until an autopsy was performed. Contacted Monday afternoon, Urquhart said there had been no new developments.