ROUND ROCK, Texas -- Round Rock police are still searching for a driver who fled the scene after an alleged racing accident that killed a father and his young child Saturday afternoon.

Round Rock police said the man an his child were walking on a sidewalk when the crash happened at 3:47 p.m. on A.W. Grimes Boulevard at Gattis School Road.

Witnesses told police that two cars were racing at a high rate of speed and one of the drivers lost control of their vehicle, described as a red Ford Mustang. The red Mustang flipped and clipped a van before rolling into the two pedestrians who were walking on the sidewalk. The pedestrians, identified as an adult male and a female child, were killed.

Multiple people had to be extricated from the red Mustang in unknown condition.

An unknown number of passengers in the van were transported to the hospital with injuries that are not believed to be life-threatening.

The second vehicle that was believed to be racing fled the scene. Police are searching for the vehicle, described as a blue Mustang.

An investigation into the crash is ongoing. If you have any information about the blue Mustang or the whereabouts of the driver, contact Round Rock police immediately at 512-218-5500.