Clare Shelswell died at the hands of her stepfather after a family argument about discipline. ((CBC))

A B.C. man has pleaded guilty to killing his five-year-old stepdaughter during a family vacation in Washington state in June.

Peter Wilson pleaded guilty to first-degree murder Monday in U.S. Superior Court in Shelton, Wash., near Seattle.

Wilson was charged after the death of Clare Shelswell June 27.

Wilson changed his plea to guilty because he wanted to spare his wife and family the anguish of a trial, his lawyer, Ronald Sergi, said.

Shelswell, whose funeral in her hometown of Abbotsford, B.C., drew 500 devastated friends and family, was killed while on holiday in the community of Hoodsport, Wash.

Wilson, 30, was accused of slashing the girl's throat after arguing with her mother about discipline.

He told investigators he takes medication for bipolar disorder and initially pleaded not guilty to the murder in July.

Sergi said Wilson changed his plea and admitted his crime to spare his family from reliving the grisly details of Shelswell's death in court.

"He did not want to put his family through a trial, and he acknowledged his guilt," Sergi said in an interview Monday.

Wilson will be sentenced Oct. 22.

Exceptional sentence sought

Gary Burleson, the prosecutor in the case, said the standard sentence for first-degree murder with no prior criminal record is about 20 to 26 years. There's an additional two-year sentence for committing the crime with a deadly weapon.

Burleson said because of the aggravating circumstances of the case, he intends to ask the court for an exceptional sentence but would not specify the length of prison time he will request.

The maximum sentence is life in prison.


Peter Wilson, of Abbotsford, B.C., changed his plea to guilty in the killing of his five-year-old stepdaughter. ((CBC))

"She was a vulnerable victim; she was dependent on him," he said in an interview.

Sergi said there were no family members in court during Monday's proceedings.

He declined to comment on Wilson's current condition.

Wilson was arrested after police were called to a Hoodsport cabin after the slaying.

Investigators said Shelswell's throat had been slashed through the windpipe and Wilson was "stoic" as he was taken into custody.

The girl's mother told police she and Wilson had argued about discipline and he told her "he would take care of it."

The mother told police she heard a scream a short time later and found her daughter in a pool of blood.

Investigators say Wilson told them he knew he was going to kill Shelswell with a knife he found on the kitchen counter.