LOS ANGELES — Prosecutors declined Tuesday to file criminal charges against former U.S. Commerce Secretary John Bryson, saying a seizure caused a bizarre series of traffic collisions that led to his resignation.

On June 9, Bryson’s Lexus struck a car that was stopped for a train in San Gabriel. He spoke briefly with the three occupants then hit the car again as he departed, police said. Bryson then rammed another vehicle in a neighboring city a few minutes later. He was found unconscious in his car.

The Commerce Department said at the time that Bryson had a “limited recall of the events” and had had no previous seizures.

Bryson, 68, was cited by police for felony hit-and-run, and tests revealed he didn’t have any alcohol or drugs in his system. Low amounts of Ambien were found in his bloodstream, but investigators couldn’t determine if the sleep aid was a factor in the collisions.

“Both treating doctors agree that suspect was suffering from confusion following a seizure and crashed as a result,” court documents say. “Based on doctors’ opinions there is insufficient evidence to show knowing failure to provide personal information for hit-and-run.”

Phone messages left for Bryson’s wife, Louise, were not immediately returned.

Police in San Gabriel, a community of about 40,000 people northeast of Los Angeles, presented evidence Monday to county prosecutors, who decided against filing charges.

Police Sgt. Brian Kott declined to discuss the decision and said his department made no recommendations about filing charges.

Bryson resigned as commerce secretary June 21, saying then he had had a seizure and didn’t want his health to be a distraction from his job.