Sebastopol man charged with felony gross vehicular manslaughter in death, serious injury of bicyclists

A Sebastopol man has been charged with three felony counts of gross vehicular manslaughter and driving under the influence in connection to a May 12 crash in which a bicyclist died and another lost a leg.

The criminal complaint from the Sonoma County District’s Attorney’s Office offers a preview of what Ulises Valdez Jr. of Sebastopol will face in court when he is scheduled to enter a plea on July 21. According to Sonoma County Deputy District Attorney Brian Staebell, Valdez, the son of the late founder of Valdez Family Winery, could be sentenced to up to 12 years and four months in prison.

The complaint accuses Valdez of “unlawfully, and without malice,” killing Mark Graham Osborne, 53, of Santa Rosa. Valdez is charged with showing “gross negligence” in driving his truck.

Osborne, who died May 20 of his injuries, was a native of Australia and an enologist at Gary Farrell Winery in Healdsburg. He was also a skilled outdoorsman. He was a competitive mountain biker and marathoner.

The identity of the second bicyclist, a 12-year-old boy who was unrelated to Osborne, was not released because he is a minor, but the complaint says the boy lost a leg as a result of the crash.

Each charge includes various enhancements, for driving under the influence while having a blood alcohol level over the state limit of 0.08%, for acting illegally and/or negligently while driving and causing great bodily injury and death, according to the complaint. If convicted Valdez will not be allowed to own guns or ammunition.

“These are the charges I expected to be filed when I first heard about this case,” said Valdez’s attorney, Stephen Gallenson.

He said the case is “still in the discovery stage — a lot of the information we have requested we don’t have yet. It’s a tragic case, really sad.”

Valdez, 27, is still recovering at home from a fractured neck and is wearing a large brace restricting his neck movement, Gallenson said.

“He’s a nice young man who made a terrible mistake,” he said.

At the time of the crash, the two bicyclists were riding north separately on the right shoulder of High School Road south of Gaye Road in Sebastopol.

Valdez, driving a Ram Rebel pickup, approached the bicyclists from behind on High School Road, driving faster than the speed limit, and lost control on a left curve in the road, the CHP said at the time.

Valdez drove onto the shoulder and collided with the 12-year-old, continued out of control back into the traffic lane, then back onto the right shoulder, where the truck struck Osborne. The pickup then drove off the road and crashed into a utility pole and a tree, the CHP said. A blood test after the crash found Valdez’s blood alcohol level to be 0.15%, nearly double the legal limit.

Valdez was arrested on suspicion of felony driving under the influence of alcohol after being taken to Memorial Hospital with significant injuries along with the two bicyclists at the time of the crash, the CHP said. He suffered significant injuries and was released to the hospital’s custody at the time, authorities said.

Valdez manages the wine-growing portion of the business at Valdez Family Winery, which was founded in 2004 in Healdsburg by Ulises Valdez Sr., who died in 2018.

You can reach Staff Writer Kathleen Coates at or 707-521-5208.

Kathleen Coates

Windsor and Cloverdale, The Press Democrat 

As someone who grew up in a small town, I enjoy covering what's happening in Windsor and Cloverdale, which are growing in their own unique ways.  I delve into issues by getting to know people and finding out what’s going on in the community. I also pay attention to animal welfare and other issues that affect Sonoma County.

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