Missing three sisters probable cause of death revealed as asphyxiation as police give heartbreaking update

In another heartbreaking update, police have confirmed the three girls who went missing last week likely died of asphyxiation while cops are yet to find their dad and suspected killer.

On Friday (May 30), Whitney Decker raised the alarm when her three daughters, Olivia, five, Evelyn, eight, and Paityn, nine, failed to return home from a planned visitation with their father.

Her ex-husband, Travis Decker, was due to drop their daughters back at their Wenatchee, Washington, home, but he never appeared.

Tragically, cops confirmed all three of the little girls were found dead at Illinois' Rock Island Campground, around 40 miles away from their home, at around 5pm on Monday, June 2.

The girls' bodies were also found near to their father's white 2017 GMC Sierra truck.

The bodies of sisters Olivia, five, Evelyn, eight, and Paityn, nine, have sadly been found (GoFundMe)

Now, the three sisters' probable cause of death has been revealed as asphyxiation as per a preliminary report filed with the Chelan County Superior Court, according to Fox 13.

Decker is still reportedly at large and has been charged with three counts of first-degree murder and first-degree kidnapping, Wenatchee Police Department have confirmed.

A manhunt is still underway to trace the whereabouts of the 32-year-old, who collected the girls from their mom on Friday.

After Whitney contacted the police in concern for her daughters' safety, she told cops her frantic calls to Decker went straight through to voicemail after he was due to return them.

Decker's truck was later seen in the west end of Leavenworth, prompting a large scale search in the wooded areas of the town.

The cause of death of the sisters has been revealed as asphyxiation (Wenatchee Police Department)

When officers searched the vehicle, personal items such as blankets, food, car seats and a wallet were found, as well as two bloody handprints, reports The NY Post.

Cell phone data also reveals the man drove to and from the campsite where the girls were found dead a day before the alleged kidnapping.

Decker is believed to be homeless and stays in his car or at campsites and hotels in the local area with his dog.

His ex-wife, whom he has been divorced from for several years, said he has been showing signs that he was struggling with his mental health.

Law enforcement has now issued a warning to the public not to approach Decker if they see him, saying he poses a 'significant risk' due to his military background in mind. It is also unknown if he is armed.

While members of the public are urged not to approach Decker, police are appealing for assistance to help locate him.

Travis Decker is still at large and police have urged the public to not approach him if seen (Fox13 Seattle)

He is described as being 5 feet 8 inches tall, 190 pounds, with black hair and brown eyes, and was last seen wearing a light-colored shirt and dark shorts.

Should a member of the community see Decker, they should call 911.

A GoFundMe set up to help support Whitney with expenses and legal costs after the death of her daughters further reveals the weight of the tragic loss on the family.

The fundraiser, which has raised more that $349,000 at the time of writing, reveals the three girls enjoyed dancing and theater.

It reads in part: "We are heartbroken to share that the girls have since passed. Their light touched so many, and the pain of this loss is immeasurable."

Donations can be made to the fundraiser here.

If you have experienced a bereavement and would like to speak with someone in confidence, contact The Compassionate Friends on (877) 969-0010.

Or, if you or someone you know is struggling or in crisis, help is available through Mental Health America. Call or text 988 to reach a 24-hour crisis center or you can webchat at 988lifeline.org. You can also reach the Crisis Text Line by texting MHA to 741741.