Authorities are trying to figure what killed a Mankato man who fell from his motorcycle Saturday night on Hwy. 169 west of Mankato.

The State Patrol suspects a medical condition may have played a role, according to a statement, and Blue Earth County officials are investigating.

The motorcyclist was a 52-year-old from Mankato, the patrol said, and he was wearing a helmet. His name was not released, pending the notification of relatives.

The 2007 BMW motorcycle was going east on Hwy. 169 near Blue Earth County Road 33 about 6:25 p.m. when the man fell, the patrol said.