DEWEY COUNTY, Okla. (KFOR) – Troopers in Dewey County are investigating a deadly crash that killed three people.

Around 2 p.m. on March 13, emergency crews were called to an accident along US-270, just northwest of Oakwood in Dewey County.

Investigators say a 2016 International semi-truck, driven by 29-year-old Kordan Sandridge, was heading northbound on US-270 when it went left of the center for an unknown reason.

It then hit a 1999 Peterbilt semi-truck, driven by 39-year-old Martin Rodriguez-Rojo, head-on in the southbound lane.

As a result of the crash, the Peterbilt semi-truck rolled and left the road, while a 2012 Ecoline also left the road to avoid the collision.

Investigators say the drivers of both semi-trucks, Sandridge and Rodriguez-Rojo, were pronounced dead at the scene of the crash.

A passenger in the 2016 semi-truck, 21-year-old Lexxionne Dedner, was flown to an Oklahoma City hospital in critical condition.

Dedner was pronounced dead at the hospital on March 14.

At this point, troopers are still trying to figure out what caused the crash.