Two people picking up trash along a western Wisconsin highway came across the remains of a man who authorities believe had been there "for a period of time," authorities said Monday.

The discovery by a husband and wife out picking up litter was made shortly before 10 a.m. Sunday in Onalaska along Hwy. 53 just south of Sand Lake Road, according to police.

Officers secured the scene to protect the evidence and quickly determined the remains were human, police said.

There was no immediate word on the man's identity or what led to his death.

It appears "the remains had been at that location for a period of time," a police statement read. Police Chief Charles Ashbeck said, "I'm comfortable saying months," when he was asked to elaborate on Monday.

Other agencies joined police to help collect any other evidence in the brush or near a tree line along the embankment of southbound Hwy. 53.

"At this time, the identity of the remains is unknown and may take several weeks or longer to make a positive identification," police said. Ashbeck said the remains are a man's, based on preliminary information.

The chief said it's too soon to know for sure whether foul play was involved, but "we don't see any obvious signs. Obviously, an autopsy has to be performed."

PAUL WALSH