The causes of death for the three Washington sisters who vanished while visiting their father have been revealed.

According to Fox 13 Seattle, a preliminary report submitted to the Chelan County Superior Court suggests that Paityn Decker, 9, Evelyn Decker, 8, and Olivia Decker, 5, most likely died from asphyxiation.

The police discovered the girls’ bodies at 3:45 p.m. on Monday near their father’s white 2017 GMC Sierra truck at Rock Island Campground in Chelan County, as stated by the Wenatchee Police Department on Tuesday.

Authorities have not yet located the father, Travis Decker, 32, who is currently facing charges of three counts of first-degree murder and one count of kidnapping.

“It is unknown whether Decker is currently armed, but he may pose a significant risk, if approached,” police said of the defendant, who reportedly has extensive military training.

Police found Decker’s vehicle near where the girls’ bodies were discovered, marked by “two bloody handprints.” Inside, they reportedly found personal items, including blankets, food, car seats, and a wallet on the center console. A tent and cooler were also located a short distance away.

Decker’s “drove to and left the same campground a day prior to the kidnapping,” according to his cellphone activity.

As CrimeOnline previously reported, the children left with Decker on May 30. The police department stated that Decker is “homeless and living in his vehicle, or at various hotels, motels, or campgrounds in the area.”

“The visitation was part of a parenting plan, but he has since gone outside the parameters of it, which is not normal and cause for the alarm,” police said.

Decker and the children’s mother divorced several years ago, and had a parenting plan allowing him to see the girls during specific hours every other weekend.

Court documents stated that Decker’s ex-wife claimed he was diagnosed with borderline personality disorder but likely didn’t take medication for it.  The parenting plan required him to seek mental health help, along with anger management counseling, but he reportedly refused.

Anyone with information on Decker is urged to call 911 immediately and refrain from approaching home.

He’s described as a white male who stands at 5 feet, 8 inches tall and weighs 190 pounds. He was last seen wearing a light shirt and dark shorts.

Check back for updates.

[Feature Photo via Facebook]