A 13-year-old Copperopolis girl was killed in a four-car collision on Tuesday south of San Andreas.

The accident happened when a 2016 Chevrolet Colorado driven by Klayton Powell, 25, of Jamestown, crossed the center line on Highway 49 into the path of an oncoming procession of three vehicles, said San Andreas-area CHP officer Tobias Butzler said.

Butzler said an investigation was underway to determine why the vehicle crossed into the southbound lane, which includes a mechanical evaluation of the truck.

“We’re investigating how it occurred and will explore all options, if fatigue or distracted driving played a factor in this collision,” Butzler said.

About 9 a.m., Powell was driving northbound on Highway 49 south of Fricot City Road on the outskirts of San Andreas and sideswiped a 1993 GMC Yukon driven by Matthew Coldwell, 45, of Mountain Ranch.

Powell’s Chevrolet then sideswiped the next vehicle, a 2000 Saturn Vue driven by Daniel McCubbins, 37, of Copperopolis. Jennifer McCubbins, 37, of Copperopolis, was seated in the passenger seat, and a 13-year-old girl was in the left rear seat.

The hit on the Vue was “a little more severe than what the first impact was,” Butzler said.

Butzler said the girl was related to the driver and passenger, but he was not sure if she was their daughter.

The McCubbins’ car went down an embankment on the west side of Highway 49.

Powell’s vehicle was traveling across the southbound lane toward the west side of Highway 49 and made “more of a head-on collision” with the last vehicle in the procession, a 2017 International driven by Brayan Morales, 26, of Foothill Farms. The vehicles hit passenger-side headlight to passenger-side headlight, and most of Powell’s vehicle was on the shoulder before it overturned down an embankment on the west side of Highway 49.

Powell sustained minor injuries but did not require medical attention.

Daniel McCubbins and Jennifer McCubbins sustained moderate injuries and were both transported to Memorial Medical Center in Modesto.

The girl was pronounced dead at the scene.

Coldwell and Morales sustained minor injuries and did not require additional medical attention.

Everyone was wearing a seatbelt, Butzler said.

Butzler said this was the eighth fatal collision in the San Andreas CHP area this year, with a total of 10 deaths.

Contact Giuseppe Ricapito at (209) 588-4526 or gricapito@uniondemocrat.com . Follow him on Twitter @gsepinsonora.