A lawsuit filed Tuesday by the parents of one of the softball players killed in a collision between a bus and tractor-trailer last month alleges that the truck driver was under the influence at the time of the crash.

Four student softball players from North Central Texas College died and a dozen more were injured  in the accident on Interstate 35 near Davis, Oklahoma. The team was returning after a scrimmage against an Oklahoma team.

The 18 wheeler was travelling northbound on I-35 when the road veered to the right; the truck continued straight, striking the bus in the southbound lanes of the highway. According to crash scene investigators, truck driver Russell Staley said that he was distracted by something in the cab.

Audry and Christi Pelton, parents of accident victim Jaiden Rayne Pelton, filed a claim in Murray County District Court on Tuesday. The lawsuit alleges Quickway Carriers Inc., the company that owns the truck operated by Staley, was negligent in their hiring of the driver.

The claim also alleges that Staley failed to “devote his full time and attention to driving the semi,” “failed to maintain a safe speed,” and was “under the influence of one or more intoxicating substances.”

The truck accident lawsuit filed against Staley, Quickway and an insurance company, seeks damages in excess of $10,000.