MythBusters star Jessi Combs has died at age 36. Terry Madden, a member of Combs’ crew, confirmed that the MythBusters star passed away in an Instagram post, sharing a montage video of his time with Combs, who was also a race car driver. Madden said that Combs died “in a horrific accident,” adding that he “was the first one there and trust me we did everything humanly possible to save her!!”

In a press release, Oregon’s Harney County Sheriff’s Office said that a 911 call came through at approximately 4:00 p.m. on Tuesday. According to the release, the caller said that “a jet car attempting to break a land speed record on the Alvord Desert had crashed leading to one fatality.” The release also stated that deputies identified the driver of the vehicle as Combs, who was pronounced deceased at the scene. The cause of the crash is currently unknown and the case remains under investigation.

Combs hosted MythBusters from 2009 and 2010 and also hosted TLC’s Overhaulin’ from 2012 to 2014. Prior to that, she co-hosted Spike TV’s XTreme 4X4 for five years.