But his promising career and $132,000-a-year job ended with a car crash at 12:45 a.m. Aug. 10 in Walnut Creek while Sarna appeared to be driving under the influence, which led him to quit Friday.
"He offered to resign, and we accepted his resignation," said Brown spokesman GarrethLacy, who declined further comment.
Sarna expressed regret in his resignation to the Justice Department but said he made a mistake and accepts the consequences. Sarna could not be reached Monday for comment.
Sarna's state-owned 2007 Chevrolet Tahoe collided with a tow truck while trying to pass on the eastbound Highway 24 Ygnacio Valley Road exit in Walnut Creek, said California Highway Patrol Sgt. Les Bishop, a spokesman for the Golden Gate Division.
Officers said Sarna appeared intoxicated but refused a request for a field-sobriety test.
"The officer took him into custody and brought him to the CHP's Martinez office for a breath test," said Sgt. Les Bishop of the California Highway Patrol. "Based on the test results, Sarna was arrested on suspicion of driving under the influence."
He was issued a citation for a misdemeanor DUI and was then released.
No one was injured in the crash, which heavily damaged the state car.
Sarna remained on administrative leave with the Justice Department for about a week during investigation of the incident.
Sarna, a 37-year-old Clayton resident who commuted to work in Sacramento, had been in law enforcement for 16 years.
While Brown was mayor, Sarna headed special operations, including gang-suppression efforts. He'd taken on similar responsibilities at a statewide level.
Sarna, as a sergeant, was among a select few Brown asked to respond to a domestic dispute involving former Brown confidant Jacques Barzaghi in July 2004. Barzaghi was fired later that year amid sexual abuse allegations and other charges.
In January 2005, Sarna was promoted to lieutenant. In January, Brown named Sarna deputy director of the Justice Department's Law Enforcement Division, where he helped oversee hundreds of department investigators and other employees.
Sarna had a reputation in the department and community of being a confidant of Brown.
MediaNews staff writer Malika Fraley contributed to this story.
Contact Steve Geissinger at firstname.lastname@example.org.