A motorcyclist crashed after trying to stand on his seat Sunday night and later died from his injuries.

Garth Mortimer, 49, died of head trauma including a skull fracture, according to the Spokane County Medical Examiner.

At around 6:40 p.m., Spokane County Sheriff’s deputies responded to the crash on the 6900 block of N. Wall St.

Witnesses saw a man driving a Harley-Davidson north on Wall Street who tried to stand on his seat and then slipped and fell, according to a sheriff’s office news release.

Mortimer was wearing a helmet, but it was not properly fastened.

The motorcycle continued forward and hit a parked pickup, according to the release.

Mortimer was transported to the hospital but died shortly after.