A Minnesota State Patrol trooper who is accused of speeding without lights or sirens on before he killed an 18-year-old in a crash was charged Tuesday with manslaughter and vehicular homicide. Trooper Shane Roper was “driving recklessly and without regard to very basic rules of the road” when he crashed into a Ford Focus and killed Olivia Flores in Rochester in May, Olmsted County Attorney Mark Ostrem said. Criminal charges of second-degree manslaughter and criminal vehicular homicide, as well as other counts of criminal vehicular operation, were filed Tuesday, Ostrem said.

The deadly crash happened at around 5:44 p.m. on May 18 near a mall in Rochester, a city of around 121,000 in the southeastern part of the state.

Authorities alleged he was driving 83 mph in a 40 mph zone shortly before the crash. “Trooper Roper, violating his duty in such a gross fashion, caused the death of a young lady celebrating her impending graduation from high school,” Ostrem . Roper, 32, was on duty and had stopped on a highway entrance ramp doing traffic enforcement when he sped off “after observing an apparent petty traffic offense,” a Rochester police officer wrote in an affidavit that is part of the criminal complaint.

Roper then exited the highway and was driving 83 mph in a 40 mph zone eastbound on 12th Street SW as he approached an intersection that leads to the Apache Mall, police said in the document. A Ford Focus going in the other direction tried to turn left toward the mall.