A Jefferson County sheriff’s deputy who followed a motorcycle on a high-speed chase before accidentally hitting a Rigby motorist is on trial for misdemeanor vehicular manslaughter.

Opening arguments began Monday over Deputy Ken Havlicak’s April 1 pursuit of motorcyclist Casey Hosey, 20, of Rigby. Havlicak ran a stop sign at a rural intersection and crashed into 19-year-old Kent Jeppesen’s GMC Jimmy.

On April 22, Jeppesen died of injuries sustained in the collision.

Hosey later was arrested and pleaded guilty to one count of involuntary manslaughter. He is awaiting sentencing.

Havlicak’s defense attorney, Jerry Woolf, told the jury the deputy was doing his job, and the guilty party is Hosey.

Bonneville County Deputy Prosecutor Jon Shindurling’s witnesses were the first officers to arrive at the scene.

“All of a sudden the sky just had this big flash of light,” said Idaho State Police Cpl. Paul Egbert, comparing it to an electrical transformer explosion.

Egbert was training a new State Police recruit on patrol that night.

They were listening to the chase over their radio and ended up following Havlicak at a distance. Egbert had told the recruit not to join the chase because agency policy advises against pursuing motorcycles.

“I made the decision that it was not worth the risk,” Egbert said.

He said there were no skid marks on the pavement at the intersection, suggesting Havlicak did not hit his brakes before the accident.