Authorities say they may have zeroed in on the whereabouts of a wanted Rockland fugitive who disappeared after allegedly murdering his daughter-in-law four years ago.

Haverstraw investigators won't say which state he may be in, but they are working with the FBI on a credible tip about Eugene Palmer’s whereabouts.

The lifelong hunter and survivalist, who would now be 78 years old, vanished near his home into the woods of Harriman State Park after allegedly gunning down his daughter-in-law, Tammy, with a shotgun. Palmer allegedly killed his daughter-in-law after she accused his son of assault and got a restraining order, removing Palmer's son from their home, while she stayed on the family's longtime property.

Since then, investigators have scoured thousands of acres of land, and the case has garnered national attention on TV shows like John Walsh's "The Hunt."

There's been many theories over the years about what happened to Palmer, including the possibility that he died in the woods.

Investigators say they won't stop searching for him until he's found dead or alive.

Authorities say Palmer’s family has not cooperated with the investigation.