The NFL has asked a Pennsylvania federal judge to appoint a special investigator to look into alleged “widespread fraud” that is “infecting” the $1 billion concussion litigation settlement.

The National Football League on April 13 filed a motion asking U.S. District Judge Anita Brody of the Eastern District of Pennsylvania to appoint a special investigator to look into allegations that some law firms are coaching retired players to obtain more favorable scores in the claims assessment process, and some doctors are failing to properly evaluate the claimants.