Motorcyclists speeding down southbound Interstate 405 in south Renton to Interstate 5 forced a state trooper off I-5 Tuesday evening, then taunted him as he struggled trapped in his vehicle, according to the Washington State Patrol.

The trooper, 46-year-old Brian Salyer of Spanaway, was treated at Harborview Medical Center in Seattle for a mild concussion, head and neck lacerations and bumps and bruises.

Salyer, a 22-year veteran of the state patrol, radioed at about 6:30 p.m. that he was attempting to overtake a group of motorcycles traveling at more 100 mph on northbound I-5 from I-405 near Southcenter, according to the state patrol.

He attempted to get close enough to identify the lead biker, who was traveling the fastest, but two bikes intentionally cut him off, forcing him to swerve and slam on his breaks to avoid running over them, according to the patrol.

Salyer lost control of his patrol car on the ramp from I-5 to State Route 599. The car struck the guardrail and rolled over several times, coming to rest in a ditch.

As he struggled to get out of his patrol car, Salyer saw at least two of the bikers return to the collision scene and park about 30 feet away.

The motorcycle riders got off their motorcycles and began “taunting him by clapping and laughing at him as he lay bleeding and struggling within the wreckage,” according to a patrol press release.

The riders rode off quickly as other motorists began arriving and assisted the trooper by calling 911, according to the state patrol.

Firefighters extricated Salyer from his vehicle.

Early in the investigation, the state patrol was withholding information and descriptions of the riders until detectives could contact potential witnesses and collect evidence.