Cause of Death Revealed for 3 Sisters Who Vanished During ‘Planned Visitation’ with their Dad as He Remains Missing: Reports

The official causes of death of the three young sisters who were found dead after vanishing while visiting their father have reportedly been revealed.

Paityn Decker, 9, Evelyn Decker, 8, and Olivia Decker, 5, who were last seen on May 30 and found dead on Monday, June 2, most likely died by asphyxiation, according to a preliminary report filed with the Chelan County Superior Court, Fox 13 Seattle reported.

This update comes as authorities continue their manhunt for the girls’ father, 32-year-old Travis Decker.

The Wenatchee Police Department confirmed that the girls were found dead on Monday, June 2, after investigators located Decker’s 2017 white GMC Sierra pickup truck near the Rock Island Campground in Chelan County, though Decker himself could not be located. Police did not share the girls’ causes of death or the exact location where their bodies were found at the time.

Decker has been newly charged with three counts of first-degree murder and one count of kidnapping, according to police. He is already facing custodial interference charges. “It is unknown whether Decker is currently armed, but he may pose a significant risk, if approached,” police said, adding that the father has former military experience.

Fox 13 Seattle reported that Decker’s vehicle was found “with two bloody handprints” nearby where the girls’ bodies were located. Various personal items were reportedly found inside, including blankets, food, car seats and a wallet “on the center console.” A tent and cooler were also located “a short distance away,” indicating signs of recent activity in the camp, according to the outlet.

Court documents obtained by Fox 13 Seattle also reportedly stated that Decker’s cell phone activity showed “he drove to and left the same campground a day prior to the kidnapping.”

The girls were first reported missing on May 30 after they had not returned on time from a “planned visitation” with Decker. Police said at the time that Decker was “homeless and living in his vehicle or at various hotels/motels or at 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 added in their statement.

On May 31, Washington State Patrol issued an endangered missing person alert, declaring the girls and their father “at-risk/missing.” Officials also shared a photo of Decker’s vehicle. While the search lasted through the weekend, authorities canceled the endangered missing persons alert on Monday, June 2, due to the discovery of the girls’ bodies.

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A GoFundMe page set up for the girls’ mother, Whitney Decker, described their death as “heartbreaking.”

“We are heartbroken to share that the girls have since passed … the pain of this loss is immeasurable,” organizer and friend Amy Edwards wrote. “I’ve known Whitney for years, we’re both dance moms and theater friends [and I’ve] had the privilege of teaching Whitney’s girls.”

Edwards said the funds raised would cover funeral expenses as well as “support time off from work, and give her space to heal without financial pressure.” The page so far has raised $347,200 with a goal of reaching $380,000.

PEOPLE has contacted the Chelan County Superior Court and Chelan County coroner’s office for comment but did not immediately hear back.