Bicyclist killed on Petaluma road by suspected DUI driver

A bicyclist riding on a Petaluma road was struck and killed Tuesday morning by a suspected drunken driver who then crashed into an oncoming pickup truck.

John Dethlefsen, 65, of Petaluma, was arrested on suspicion of felony DUI and vehicular manslaughter, Petaluma police said in a news release.

Officers responded to the fatal crash at 9:28 a.m. on Corona Road near the Highway 101 overpass. When they arrived, they found a man lying on the pavement near two cars - a white Honda Accord and a green Ford F-150 pickup - that were involved in the two collisions. The bicyclist was pronounced dead at the scene. Authorities withheld his name, pending notification of his family.

Investigators learned Dethlefsen, who drove the Honda, was traveling east on Corona Road before he crossed over the double yellow lines into the westbound lane as he approached the overpass. It appears that Dethlefsen struck the bicyclist while in the incorrect lane, police said.

Dethlefsen then continued east onto the overpass and struck the oncoming Ford F-150 as it was traveling west on Corona Road.

Dethlefsen and the driver of the pickup truck were not injured, police said. While speaking with Dethlefsen, ?officers noticed signs that he had possibly been driving while impaired and subsequently arrested him.

The cause of the collision is still under investigation. Police said they don’t yet know why Dethlefsen was in the incorrect lane of traffic, adding that his toxicology results are still pending.

Anyone with information about the crash is asked to contact Petaluma Police Traffic Officer Chris Ricci at 707-781-1275.

You can reach Staff Writer Chantelle Lee at 707-521-5337 or On Twitter @ChantelleHLee.

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