Irvine police launched a homicide investigation Tuesday after a man's body was discovered on a bike path near the Los Olivos neighborhood, authorities said.
Police responded about 7 a.m. to the bike path that runs adjacent to the southbound lanes of the 405 Freeway south of the Highway 133 toll road.
There, they found the body of 51-year-old Sidney Siemensma of Irvine, according to the Orange County coroner's office. Coroner's officials said they will perform an autopsy to determine how the man died.
Authorities had received calls from passersby who thought a bicyclist on the path had been injured, according to Irvine police spokeswoman Farrah Emami.
When investigators arrived, they determined the man was dead, she said.
"For a short time, the body was visible to passing motorists on the 405 Freeway," Emami said.
A bicycle also was visible from the freeway.
Jeremiah Dobruck writes for Times Community News.