Police Probing Campsite Where 'Killer Dad' Travis Decker Possibly Stayed

Cops are investigating a campsite found in the Washington state woods where Travis Decker is believed to have gone on the run after allegedly killing his three young daughters -- this according to Chelan County Sheriff Mike Morrison.

Sheriff Morrison tells TMZ the abandoned campsite was discovered while an associate was on a hike in central Washington ... but there's a major problem -- they can't tell if the mystery equipment was left by lazy campers or if it's a spot where Decker sought shelter while on the lam.

Morrison says investigators are DNA-testing several pieces of evidence found throughout the intense search for "killer dad" Decker ... but it's not a quick turnaround like people are used to seeing on crime shows like "CSI."

Morrison reminds us there are other homicide cases going on in Washington -- and while some items have been expedited by the lab ... he can't just push every request to the front of the line just 'cause there's media attention.

This also explains why law enforcement has not yet determined if the alleged bloody handprints found on Decker's pickup truck -- discovered just 100 yards from the lifeless bodies of his daughters on June 2 -- are his.

In other words ... have patience, folks!

Remember ... Sheriff Morrison told us this week, Decker is presumed to be alive despite likely living in the wilderness for several weeks. We've now learned authorities will assume he's alive until a body is found.

Furthermore ... military-trained Army vet Decker is still considered dangerous, but is no longer a threat to the inhabitants of the Okanogan-Wenatchee National Forest area -- mostly because detectives simply don't have a clue where he is, and there's no need to keep residents on high alert.

In fact, Chelan County's federal partners have been in contact with agencies as far away as Canada about the homicide case, according to Sheriff Morrison. But ... he notes Chelan County has been working even more closely with U.S. Customs and Border Protection.

ICYMI ... law enforcement revealed early on in the pursuit that Travis searched several questions online including ... "how does a person move to Canada” and "jobs Canada" just days before he went MIA at the end of May.

Morrison confirms law enforcement is still sifting through all potential evidence and tips ... and continues to encourage civilians to speak up if they see anything suspicious.