PUYALLUP, Wash. -- A truck hit and seriously wounded a Washington State Patrol trooper just after he issued a ticket alongside state Route 512 Thursday morning, KIRO 7 Eyewitness News reported.

A State Patrol spokesman said the driver of a box truck lost control and hit the trooper's motorcycle, pushing the trooper into the minivan he had pulled over near Puyallup.

Video: Driver Arrested After Truck Hits Trooper

The injured trooper's partner saw what happened.

"He had just cleared a traffic stop, looked up ahead, saw the van lose control and knew that his partner was up ahead. Before he could even think, he saw our trooper fly through the air," said Trooper J.J. Gundermann, a State Patrol spokesman.

The trooper is in serious condition. He was conscious as he was transported to Tacoma General Hospital.

The driver of the van and her 4-year-old child were also hurt and were taken to a hospital.

State troopers took the driver of the box truck into custody. A woman inside the truck was questioned by Washington State Patrol detectives about what happened inside the truck just before the crash.

Video from Chopper 7 showed the downed motorcycle, the crashed truck and the van as State Patrol investigators examined the scene.

The trooper who was hurt is 41 years old and is a 13-year veteran of the Washington State Patrol.

The investigation into what happened to cause the driver of the truck to lose control is under way.