WALNUT CREEK (CBS SF) — Three people were killed late Tuesday night when their car careened off an 680 off-ramp in Walnut Creek, slamming into a grove of bushes and trees and burst into flames, authorities said.

Contra Costa CHP Sgt. Jon Koven said calls came in around 10:44 p..m. of a car on fire along the 680 freeway at the North Main off ramp. Both CHP officers and a fire crew were responded.

“It appears the car took the off-ramp, went off the road and hit a tree which caused it to burst into flames,” he said.

The car was engulfed in flames when the fire crew arrived. Once the flames were extinguished, CHP and firefighters made a gruesome discovery. The three occupants of the car were not able to escape and were pronounced dead at the scene.

Koven said the coroner would identify the bodies.

The cause of the crash remained under investigation.