Mohammed Saad, 57, said that he was driving behind a young man in a Pontiac south on Folsom around 1 p.m. on Tuesday when the car stopped short in front of him just south of 16th Street.

The young man, who Saad described as thin and in his 20s, approached his car, opened the door and grabbed his keys. The assailant then took off and left Saad behind with no way to drive his car.

That may have been the point. A third party who witnessed the end of the incident said the driver of the Pontiac was indeed upset, but no one saw the incident leading up to Saad’s keys being taken.

“I stopped then he took the keys,” said Saad, who lives in Colma and was waiting to give police officers a photo of the sedan that clearly showed its license plate.

A meter officer said it sounded to him like an incident of road rage.