PORTAGE, Wis. (AP) — Prosecutors in Wisconsin have charged a semi-truck driver from Indianapolis who crashed into a school bus and injured at least 20 people, including five critically.

Forty-two-year-old Wayne Murphy was charged Wednesday with five counts of injury by intoxicated use of a vehicle and five counts of second-degree reckless injury.

Murphy was driving a semi that struck a bus on the side of the interstate near DeForest on May 23. The bus had pulled over because of mechanical problems.

According to the complaint, Murphy was under the influence of prescription medication at the time of the crash. The complaint also says he did not seem concerned about the injured children.

The bus was carrying about 30 people from Hope Christian School in Milwaukee.

WISC-TV reports Murphy is due back in court Thursday.