Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

The Philadelphia Flyers' mascot, Gritty, is being investigated in connection with allegations of an assault involving a 13-year-old boy, police said.

The incident happened during a November photo shoot with fans and the 7-foot furry orange creature at the Wells Fargo Center.

Chris Greenwell, the boy's father, said the Flyers invited him and his son to meet Gritty to thank them for being season ticket holders, The Philadelphia Inquirer reported. But what was supposed to be a fun evening with the hockey team's mascot quickly turned sour.

Greenwell told the newspaper that after the photo was snapped, his son playfully patted Gritty on the head. The mascot hopped out of his chair, "took a running start" and punched the teenage boy in the back, Greenwell alleged.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

In an email to officials at Comcast Spectacor, which owns the Flyers, Greenwell called Gritty's actions "unprofessional and unacceptable," according to The Inquirer.

Comcast Spectacor and NBCUniversal, which owns NBC News, are subsidiaries of Comcast.

Download the NBC News app for breaking news

"I know it was not correct for my son to harmlessly tap him on his head but for a Flyers employee to get [sic] throw a full punch at someone with his back turned and hurt a 13 year old boy is assault, unprofessional and unacceptable for your organization," the email said. NBC News has not verified the email.

Greenwell also took issue with how the photo turned out, telling officials that Gritty was not looking at the camera.

The Flyers said in a statement Wednesday: "We took Mr. Greenwell's allegations seriously and conducted a thorough investigation that found nothing to support this claim."

Greenwell said he took his son to a chiropractor and was told that the teen had a back bruise and had suffered mild pain, according to The Inquirer. He also contacted officials at Comcast Spectacor about how the situation could be resolved.

When an agreement could not be reached, Greenwell contacted the police.

A police spokesperson said the investigation "is active and ongoing."