An autopsy Tuesday failed to explain why a 33-year-old man was found dead last week along the banks of the Animas River, La Plata County Coroner Jann Smith said.

“We didn’t find anything,” she said.

Around midnight Thursday, a report came in to authorities of a body lying on the ground near the Ninth Street Bridge.

Upon investigation, the man was found to be deceased. He was identified as Manuel Shirley, who Smith said was part of the homeless community in Durango.

Smith said there were no obvious signs at the scene of why Shirley died, though no foul play was suspected.

Smith said it is unusual that after an autopsy authorities still don’t know why Shirley died. She said a toxicology test may shed more light on the situation, the results of which will take about four weeks.

Smith said she was able to locate next of kin in Arizona.

Calls to Durango Police Department Cmdr. Ray Shupe were not immediately returned Tuesday afternoon.