Yellowstone County authorities are investigating after a man's body was found in Alkali Creek near MetraPark.

Sheriff's Capt. Bill Michaelis tells The Billings Gazette a hiker on a walking path called 911 late Tuesday morning to report a possible body floating in a pool on the creek.

Emergency crews found the man's body floating face down.

Alkali Creek runs under Bench Boulevard and through a marshy area before tumbling down a steep, rocky hill and collecting in a small pool.

Michaelis said it is not known how long the man's body was in the water.

An autopsy was planned to determine the cause of death.