The California Highway Patrol (CHP) is investigating a two-vehicle crash that claimed multiple lives on Sunday.

The crash occurred shortly after 8 p.m. on August 14 in Hollister, California.

According to CHP, the Tesla was eastbound on Highway 156 near Fairview when the vehicle veered into oncoming traffic, striking a semi truck head-on.

All four people inside the Tesla were killed in the crash.

No other injuries were reported.

The victims have been identified as middle school students Lucy, Leigh, and Ben Biakanja. Their mother Lisa Biakanja, 55, was driving the Tesla.

CHP is investigating whether the Tesla was in self-driving mode when the crash occurred. KSBW reports that a family member says that the Tesla was a 2014 model that was not equipped with self-driving capabilities.