KINGFISHER COUNTY, Oklahoma - The Oklahoma Highway Patrol said four people have died following a crash involving a semi in Kingfisher County Tuesday evening.  

According to OHP Spokesperson Sarah Stewart, the crash occurred just before 7:30 p.m. at U.S. Highway 81 and County Road 850. 

OHP said the vehicle traveling southbound on US 81 struck the rear trailer of a parked semi. 

According to the report, the driver of the vehicle, identified as 39-year-old Kenneth Sanford Marshall, 62-year-old Kenneth Marshall and a 24-year-old unidentified woman died at the scene. Two of the victims were pinned inside of the vehicle for more than four hours and eventually freed by Kingfisher firefighters, officials said. 

The fourth victim, identified as 52-year-old Adeanna Marshall, was medi-flighted to OU Medical in critical condition but later died from her injuries. 

The fifth passenger, Mikeal Jantz, 30, was taken to OU Medical and is reportedly in critical condition.

Officials said the driver of the semi, 53-year-old Jess Allen Parsons, was taken to Mercy Hospital in Kingfisher where he was treated and released.

At this time the cause of the crash remains under investigation.