Prosecutors are moving to drop charges against Travis Decker, accused of killing his three young daughters in May, after the U.S. Marshals Service reported he is believed dead.

Authorities discovered human remains in a remote wooded area south of Leavenworth, Washington, on Sept. 18, but DNA tests are still pending to confirm the identity.

Decker, 32, a former Army infantryman, was accused of suffocating his daughters—Paityn, 9, Evelyn, 8, and Olivia, 5—whose bodies were found with his truck in the Cascade Mountains.

His ex-wife had previously cited worsening mental health and instability, noting he often lived out of his truck, CBS News has reported.

Decker’s military training in survival and navigation had complicated the search, which spanned months before his presumed death.