Philadelphia police are reportedly investigating a claim that the official mascot for the Philadelphia Flyers, Gritty, punched a 13-year-old boy during a photo session. The Philadelphia Inquirer reports that Chris Greenwell and his son—Brandon—were at a Nov. 19 photo shoot with the mascot when the teenager patted Gritty on the head. Greenwell told the newspaper that Gritty then “took a running start” and “punched [his] son as hard as he could” in the back. The father claims his son had to see a chiropractor after the incident and was diagnosed with a back bruise.

In an email to Comcast Spectator—the company that owns the Flyers—after the alleged incident, Greenwell wrote that the mascot throwing “a full punch at someone” was “assault, unprofessional and unacceptable for [their] organization.” Comcast Spectator officials told Greenwell they had no video footage to corroborate his claim, and a probe into Gritty and “Gritty’s handler” could not verify his claims either. Nonetheless, Comcast Spectator offered Greenwell perks for his “bad experience”—but the two parties could not come to an agreement. The father filed a police complaint on Dec. 21, and police said a probe into the alleged “physical assault” was “active and on-going.” Comcast Spectator and Gritty have not commented publicly on the matter.