CATOOSA, Oklahoma - The Oklahoma Highway Patrol is investigating what caused a pickup to slam into the back of a semi on Highway 412 near the Creek Turnpike exit Sunday evening.

Troopers tell News On 6 the 2010 GMC Sierra pickup was dragged for almost a mile after the 7:05 p.m. crash.

The pickup's driver, 30-year-old Zachary Helms of Broken Arrow was taken to a Tulsa hospital in critical condition where he died hours later. A 9-year-old male passenger in Helm's truck was taken to a hospital in critical condition. 

The OHP report states Helms and his passenger were pinned in the wreckage until they could be freed by the Catoosa Fire Department.

Troopers said the semi driver, 55-year-old Shamsher Singh of Stockton, California and a passenger, 47-year-old Amarjit Singh from La Plata, Maryland were not injured.