Authorities in Washington state searching for an ex-military man accused of killing his three young daughters have noted the possibility that he may already be dead.

The manhunt for 33-year-old Travis Decker, who is accused of murdering his daughters, 9-year-old Paityn, 8-year-old Evelyn, and 5-year-old Olivia, turned a new page after the Kittitas County Sheriff’s Office stated in a Facebook post on Monday that “there is no certain evidence that Decker remains alive or in this area.” The search for Decker currently spans two counties, and state and federal agencies have joined the search, including the U.S. Border Patrol and the U.S. Marshals Service.

Chelan County Sheriff Mike Morrison told USA Today on Monday that, in addition to “additional air operations” and “specialized search teams,” cadaver dogs would also be deployed in the search for Decker.

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According to the Kittitas County Sheriff’s Office, “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.” Decker has been described as a survivalist who has gone off the grid for more than two months at a time.

The three girls were found dead on June 2, days after their father picked them up for a scheduled visitation and never returned them to their mother. All three girls died of suffocation and were found with plastic bags over their heads, their wrists zip-tied.

Authorities raised the possibility that Decker may be heading for the U.S.-Canadian border. An affidavit from a U.S. Marshals Service agent stated that Decker had reportedly conducted internet searches for “how does a person move to canada,” “how to relocate to canada,” and “jobs canada” in the days before he allegedly murdered his daughters.