Dad kills 6-year-old daughter in murder-suicide; what happened to this girl's mother?(Pierce County, Washington)

We're told by a neighbor that the killer and his daughter "kept to themselves" (translation: control freak father kept young daughter isolated from other people). Dad was apparently being evicted and "acting suicidal" before the murder. No mention of a mother anywhere. I'm thinking UNNAMED DAD was custodial. But how? Who gave him custody? What happened to this murdered girl's mother?

http://www.king5.com/story/news/local/2014/11/25/murder-suicide-puyallup/70125410/

Father, young daughter found dead in an apparent murder-suicide

Janet Kim, KING 5 News 7:43 p.m. PST November 25, 2014

PUYALLUP, Wash. -- A man and his young daughter were found dead inside their South Hill apartment in Puyallup Tuesday morning. Pierce County investigators believe it's the result of a murder-suicide.

According to the Pierce County Sheriff's Department, neighbors told investigators the father was packing up his SUV because he was scheduled for eviction from his apartment along the 17700 block of 85th Ave. Ct. E. They said he was acting suicidal Monday night and saying he was going far away.

Pierce County sheriff's deputies came to the home for a welfare check Tuesday morning after a concerned neighbor called. Deputies reported seeing the 6-year-old girl through the window and forced their way inside; they found both the child and her father dead.

Neighbors said the man and his daughter kept to themselves. Investigators said there was no history of trouble at the home.