A memorial service will be held Friday for Douglas Martin Rosoff, a Ukiah psychiatrist and avid bicyclist killed Friday when he collided with a dump truck.

Rosoff was 56. Police have yet to determine who was at fault in the Ukiah crash.

Employees at Mendocino County's mental health department, where Rosoff worked for 17 years, are reeling from the loss, said Jeanine Miller, a supervisor and psychologist with the department.

"He was an amazing man and he touched so many lives," she said.

Rosoff was Mendocino County's chief psychiatrist until he retired from that post last year. He most recently was working at the Ukiah Veterans Administration medical clinic. Rosoff also provided expert psychiatric testimony in court on occasion.

His former co-workers at the county remembered him Wednesday as compassionate, caring and smart. He was committed to his work and willing to make himself available in emergencies, they said.

"He was always available to everyone in the community," Miller said.

Cheri Heffel, a nurse practitioner at the Veterans Administration clinic who also had worked for years with Rosoff at the county, recalled him as "a humble, gentle, kind soul."

Rosoff also had a light side. Miller said a co-worker recalled Wednesday how overjoyed Rosoff was when he announced he was getting married six years ago.

"He was so excited. They danced together in his office," Miller said.

Rosoff also was enthusiastic about bicycling, running marathons, tennis and his dogs.

One of his dogs, now deceased, was a regular sidekick at the mental health clinic. The black Labrador retriever, Maxine, would make rounds with him, Miller said.

"He loved Max. Max loved him," Heffel said.

Rosoff was born in San Mateo. He received his bachelor's degree at Stanford University before attending medical school at Kansas City School of Osteopathic Medicine, according to family members.

He did psychiatric residencies at Westchester Center in New York and at UC Davis.

Before moving to Ukiah 20 years ago, he worked as a prison psychiatrist at a Texas state hospital and at the Federal Correctional Institute in Rochester, Minn. He was a faculty member of TURO Medical School, according to relatives.

Rosoff is survived by his wife, Catherine Rosoff of Ukiah, parents Harold and Bernice Rosoff of Arizona, sister Leslie Westerlund of Arizona and brother Jeff Rosoff of Minnesota.

The memorial service is scheduled for 1 p.m. at the Lake Mendocino Club House on Lake Mendocino Drive. Rabbi Shoshanah Devorah will officiate.

--Glenda Anderson