LEAVENWORTH, Wash. (AP) Blood discovered at a campsite where three young Washington state sisters were found dead last week belonged to a male, authorities said Monday as the search continued for their father, a former soldier with extensive survival skills.

Investigators have been looking for Travis Caleb Decker, 32, since the night of May 30, when he failed to return the girls to their mother’s home in Wenatchee, about 100 miles (160 kilometers) east of Seattle, after a scheduled visit.

Three days later, a sheriff’s deputy discovered the bodies of 9-year-old Paityn Decker, 8-year-old Evelyn Decker and 5-year-old Olivia Decker down an embankment at a campsite in the Cascade Mountains. The campsite, west of Leavenworth, is about 11 miles (18 km) from the Pacific Crest Trail, which runs from the U.S.-Mexico border to the U.S.-Canada border.

Decker has been charged with murder and kidnapping. According to a probable cause statement filed in Chelan County Superior Court last week, Decker’s truck was left at the campsite, and it had two bloody handprints on the tailgate. In a news release Monday, the Chelan County Sheriff’s Office said tests revealed that one blood sample taken from the scene belonged to a male, and another turned out to be from an animal.

The sheriff’s office did not say whether the tested samples had been taken from the tailgate. DNA and fingerprint analyses are pending, the news release said. Decker’s dog was also found alive at the scene and turned over to the humane society for care.

The sheriff’s office said that while it is retaining command of the criminal investigation, it had turned over control of the search efforts to federal authorities to give its personnel time to rest. Officials have searched hundreds of square miles, much of it mountainous and remote, by land, water and air.

Decker has also been charged in federal court with unlawful flight to avoid prosecution. According to an affidavit filed by deputy U.S. marshal Keegan Stanley in that case, Decker has training in navigation, survival and other skills that make him “a very avid and well-versed outdoorsman.”

Decker once spent 2.5 months in the backwoods living off the grid, Stanley wrote, and in the days before he took the girls, he searched online for how to relocate to and find a job in Canada.

Decker was an infantryman in the Army from March 2013 to July 2021 and deployed to Afghanistan for four months in 2014, according to Army spokesperson Lt. Col. Ruth Castro. From 2014 to 2016, he was an automatic rifleman with the 75th Ranger Regiment at Joint Base Lewis-McChord in Washington.

Last September his ex-wife, Whitney Decker, wrote in a petition to modify their parenting plan that his mental health issues had worsened and that he had become increasingly unstable, often living out of his truck. She sought to restrict him from having overnight visits with the girls until he found housing.

An autopsy on Friday determined the cause of death to be suffocation, the sheriff’s office said. The girls had been bound with zip ties and had plastic bags placed over their heads.

Authorities have reopened popular camping and backpacking areas in the Icicle Creek area, near where the girls were discovered. Other trails in the Lake Chelan National Recreation Area have reopened for day use but not camping.