() Authorities have acknowledged there’s a “potential” that manhunt subject Travis Decker is “deceased” as the manhunt for the man accused of killing his three daughters approaches its fifth week.

“We have not given up on the search efforts,” Chelan County Sheriff Michael Morris. “We recognize there is a potential that he could be deceased, so we’re also looking for that potential. We’ve got our forest service deputy out searching trails that we hadn’t yet searched. So we’re going to continue to do what we can here locally.”

Authorities have linked Decker, accused of killing his three daughters in Washington state, to blood found on a truck near the crime scene.

A manhunt has been underway since police said they found the asphyxiated bodies of Decker’s daughters, aged 5, 8 and 9, near a campsite on June 2, along with Decker’s abandoned vehicle. Decker, 32, picked up the girls May 30 for a court-mandated parental visit but did not return them to the Wenatchee home of their mother, Whitney.

“We still want to bring closure to the family and pay respects for Peyton, Evelyn and Olivia,” said Morris. “We just appreciate everyone still remaining focused, vigilant. We’re just as frustrated as anyone else that we haven’t located him yet.”

The U.S. Marshals Service is offering up to $20,000 for information leading to his arrest. Anyone with information on Decker’s whereabouts or the murders should call 911 or reach out to the nearest U.S. Marshals office.