A Baden man was killed last night when he crashed his motorcycle on Interstate 79 in Marshall, the Allegheny County medical examiner said.

Within two hours of the crash, a state police trooper on his way to investigate was injured in a collision with another vehicle.

Police said Shane Stringer, 27, was speeding at 10:02 p.m. as he rode his motorcycle south on I-79 in Marshall near the Wexford exit.

The motorcycle struck the right rear section of a vehicle that had been ahead of him. The collision caused the motorcycle to fall and slide about 260 feet before it hit a guide rail.

Mr. Stringer was dislodged from the motorcycle as it continued to slide back onto the roadway, police said.

Occupants of the vehicle, Casey Burch, 19, of East Randolph, NY, and his passenger, Diana Burch, 52, of Bushnell, Fla., were slightly injured in the accident, police said.

The motorcycle was struck by another vehicle driven by Janet Amrhein, 57, of Franklin Park, suffered minor injuries.

Mr. Stringer was pronounced dead at the scene.

At 11:55 p.m., Trooper Eric Friend, 30, was speeding toward the accident scene to assist.

The northbound police car was about a half mile from the scene with the siren and emergency lights activated when an SUV, driven by Fallon Nagle, 20, of Zelienople, was being directed around the wreckage.

As her vehicle crossed the median the police cruiser collided with the SUV's right rear section.

Tpr. Friend and Ms. Nagle were hospitalized. Their conditions were not available.