As authorities continue their search for Travis Decker, the Washington state man accused of suffocating his three daughters to death, investigators now believe he is the only suspect in the crime based on evidence found at the gruesome scene.

“The completion of this DNA analysis provides additional evidence that indicates Travis Decker is the only suspect involved in committing these homicides,” the sheriff’s office said in a release. Decker's location is still unknown, and investigators have not confirmed whether he is alive or dead.