Lake County California Highway Patrol officers are hoping witnesses saw a bicyclist before or after he crashed in the pre-dawn hours Saturday near Hidden Valley Lake.

Daniel Renninger, 21, of Hidden Valley Lake was found convulsing and unresponsive along Deer Hill Road north of Hidden Valley Road sometime after 1:45 a.m. Later investigators learned he may have crashed while riding his bicycle, the CHP said.

Emergency responders did not initially know how the man became injured and couldn’t identify him.

Renninger was flown to Kaiser Medical Center in Vacaville, where officers tried and failed to identify him with a fingerprint device. Lake County sheriff’s deputies began canvassing the area with a photograph. Eventually, Renninger’s family contacted the sheriff’s office.

Later that morning, a witness called the sheriff’s office and led authorities to believe Renninger crashed on a bike, CHP Officer Joe Wind said. CHP investigators took over the investigation after being notified at about 10:45 a.m.

Renninger was not wearing a helmet and had no front light on the bicycle when he lost control heading south on Deer Hill Road, according to the CHP.

Anyone with information about the case can call the Lake County area CHP at 279-0103.

You can reach Staff Writer Julie Johnson at 521-5220 or On Twitter @jjreport.