Disturbing new crime scene details emerge as police still on hunt for man suspected of killing his three daughters

Warning: This story contains details which some readers may find upsetting.

Police have released further details about the case of Travis Decker, the man accused of killing his three daughters.

On 2 June, the bodies of sisters Paityn, 9, Evelyn, 8, and Olivia, 5, were found at a campground in the US state of Washington. The sisters were previously reported missing by their mother after a planned custody visit with Decker on 30 May.

Decker remains missing, with authorities still unable to locate the 33-year-old despite a three-month manhunt.

In a new update on the case, authorities have released further details about the three girls' killings, including how they were killed and DNA evidence recovered from the scene.

Police are still searching for 33-year-old Travis Decker (Wenatchee Police Department)

It had previously been revealed that the sisters were each found with a plastic bag over their head and their hands zip-tied together, with a press release on Monday revealing further details.

"Two of the victims each had two separate bags over their heads, and the third victim had three separate bags over their head," the update read.

An autopsy performed on the girls had confirmed they had all died from suffocation.

Authorities also confirmed that several cable ties were recovered close to the bodies.

The update revealed the only DNA sample taken from the crime scene matched Decker, meaning there are no further suspects in the case.

"The completion of this DNA analysis provides additional evidence that indicates Travis Decker is the only suspect involved in committing these homicides," the update added.

Authorities are still unsure on the location of Decker - who CNN states is an army veteran with wilderness survival skills - despite local, state and federal offices coming the area for him.

The sisters were killed after a scheduled visit with their father (GoFundMe)

His truck was discovered close to the murder scene, suggesting that he'd fled on foot.

According to Monday's update, authorities are unsure if Decker is still alive, adding: "At this time, we do not have any evidence to suggest Travis Decker is either alive or deceased."

The latest update mirrors similar press releases shared about the case, with authorities previously saying there was 'no certain evidence' he was still alive.

"At this time, there is no certain evidence that Decker remains alive or in this area. Seemingly strong early leads gave way to less convincing proofs over the last two weeks of searching," an update released back in late June read (via UNILAD).

Some search resources are being redirected to find and recover Decker if he died in the rugged wilderness during this intense search—a possibility that increases every day. Visible extra patrols continue in the area. The US Marshals service has turned their fugitive-finding resources to the task of finding Decker if he's left our area.

A manhunt for Decker continues, despite concerns he may no longer be alive (Wenatchee Police Department)

The statement went on to add that officers will continue the search despite concerns that Decker may be deceased, adding: "Paityn, Evelyn, and Olivia Decker deserve justice. And Decker remains a danger to the public as long as he's at large. We are still asking for and will continue to investigate leads and tips from the public."

Meanwhile, friends of the girls' mother, Whitney Decker, have set up a GoFundMe to support any legal costs and expenses.