Police said the 5-year-old girl was killed at a rental home near Lake Cushman, west of Hoodsport, Sunday, where the family from Abbotsford, B.C., was vacationing.

Investigators said when deputies and medics arrived at the home in the 200 block of North Mount Seattle Way at 6:13 p.m., the girl was dead, her head nearly decapitated. Police said the child's mother, 29, and the stepfather’s sister were still inside the house. The victim’s stepfather, also 29, was in a gazebo outside the home when officers arrived, police said.

That man, identified as Peter James Wilson, is in custody in connection with the killing. He was booked into the Mason County Jail on Sunday night and is being held on $3 million bail. Wilson has not yet been charged.

Chief Deputy Dean Byrd said the girl's throat was slit with a large kitchen knife. The victim was identified as Clare Louise Shelswell.

Clare Louise Shelswell - 5 year old victim

Probable cause documents said Wilson’s wife told investigators she and Wilson argued about disciplining the girl, and Wilson told his wife he would take care of it and went downstairs with his stepdaughter.

A few minutes later, the girl’s mother heard screaming, raced down the stairs and found her daughter clutching her throat, documents said.

The victim’s mother told police Wilson was standing near the kitchen covered in blood while the victim was lying in a pool of blood, probable cause papers said.

Wilson told a detective that as soon as he started to walk down the stairs to the kitchen with the girl, he knew he was going to kill her, documents said.

"In my 37 years, this is probably the most horrific crime that I have been involved in. It's very sad for me, the department and for the community at large. It's just a horrific crime, and it's so senseless,” Byrd told KIRO 7 Eyewitness News.

Byrd said Wilson was cooperative and provided information about what happened Sunday.

Probable cause documents said Wilson told investigators he is taking medication for bipolar disorder.

Wilson is expected to be arraigned in the next 72 hours, police said.