Sommerville's cause of death was freshwater drowning, Thurston County Coroner Gary Warnock said.
The boy was playing with his brother and a cousin in the 1700 block of Overlake Court Southeast at 10:15 a.m. when he wandered off, according to Thurston County sheriffs Sgt. Alvin Griffin.
He was gone possibly as much as 10 minutes when his mom and dad went looking for him, Griffin said.
The boys mother found him in the lake and pulled him from the water. The childs father started to do CPR as medics responded.
They were working hard to revive him, but it just didnt happen, Griffin said.