ST HELENA (CBS SF) — Two people were killed early Tuesday morning in a horrific head-on crash on Highway 29 just north of St. Helena, authorities said.

The California Highway Patrol said the collision was reported at 2:15 a.m. at Bale Lane in unincorporated Napa County. Arriving officers found both vehicles completely ripped apart by the force of the crash and both drivers were declared dead at the scene.

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CHP officer Joseph Duncan said all possible causes were under investigation including driving under the influence and driving at a high rate of speed.

Investigators said a 68-year-old Yountville man was driving a 2014 Chevrolet Sonic south on the highway when the Chevrolet crossed the solid double-yellow lines and collided with a northbound 2010 Toyota Prius driven by a 32-year-old man from Lower Lake in Lake County.

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Both directions of the highway were closed for several hours while the CHP investigation was conducted.