In two separate collisions Friday and Saturday, drivers hit pedestrians, then kept on going. In both cases, the drivers were tracked down by the police, but so far only one of them is facing charges.

San Francisco Police department spokesperson Officer Gordon Shyy says that at about 3:25 p.m. on Friday, "an SFPD off-duty officer was struck by a vehicle at Leavenworth and Ellis in the Tenderloin."

The driver then fled from officers who responded to the scene, Shyy says, leading them on a chase all the way to Geary Boulevard and Steiner Street, which is near Japantown. That's where, according to Shyy, the driver crashed into another car, trapping a woman inside it.

The driver then tried to flee on foot, and was apprehended by officers soon after, Shyy says. The woman in the car that he struck was transported to the hospital. Both her injuries, and the injuries of the police officer who was struck, are non-life-threatening, Shyy says.

The driver, who Shyy declined to identify at this stage in the investigation, "faces a number of felony charges."

On Saturday, 21-year-old San Leandro man Arman Lester was headed south on his skateboard on Third Street near Cargo Way, which is about a block south of a popular skate spot at Indiana and Tulare streets, Shyy says.

That's when a driver who was also headed south, described only as a 73-year-old man, allegedly struck and killed Lester, according to police.

The driver didn't stop after the collision, initially causing police to report this as a hit-and-run. However, after the driver and his vehicle (according to the Chron, a white SUV) were located shortly thereafter, police changed their tune, with Shyy saying that "it is possible the driver did not know he struck the pedestrian."

At publication time, no charges had been announced against the driver, but Shyy cautions that "it is still an active and early investigation."

SFPD's Traffic Collision Investigations Unit was on scene, Shyy says, and is interviewing the driver and witnesses "to determine what exactly occurred."