DENVER, Colorado - Denver police are investigating a series of disturbing videos involving high school cheerleaders showing students screaming in pain as they are forced into splits by their coach. The footage was recorded earlier this summer, but surfaced this week. Five Denver public school officials have been placed on leave.

Kirsten Wakefield is the mother of one of the girls in those videos. She says her daughter quit the team because she was afraid to be in the same room as her coach. That coach was dismissed from a similar position at another Colorado high school last year for doing the same thing, reports CBS News' Dana Jacobson. 

Cellphone video shows 13-year-old Ally Wakefield pleading "please stop" nine times as she's forced into the splits by her cheerleading coach.

"I was just thinking it was normal, I didn't think much of it," Ally said.

But the high school freshman suffered from torn muscle tissue and a pulled hamstring and is receiving physical therapy.

"The doctor said 100 percent that the injury that she sustained was directly caused by the coach's knee on the back of her thigh forcing it the floor. She said that it could possibly fracture the pelvic system and reproductive organs as well," Kirsten said.

Denver police are investigating a series of disturbing videos involving high school cheerleaders showing students screaming in pain as they are forced into splits by their coach. The footage was recorded earlier this summer, but surfaced this week. Five Denver public school officials have been placed on leave.

Kirsten Wakefield is the mother of one of the girls in those videos. She says her daughter quit the team because she was afraid to be in the same room as her coach. That coach was dismissed from a similar position at another Colorado high school last year for doing the same thing, reports CBS News' Dana Jacobson. 

Cellphone video shows 13-year-old Ally Wakefield pleading "please stop" nine times as she's forced into the splits by her cheerleading coach.

"I was just thinking it was normal, I didn't think much of it," Ally said.

But the high school freshman suffered from torn muscle tissue and a pulled hamstring and is receiving physical therapy.

"The doctor said 100 percent that the injury that she sustained was directly caused by the coach's knee on the back of her thigh forcing it the floor. She said that it could possibly fracture the pelvic system and reproductive organs as well," Kirsten said.

"The world is a scary place and people you think you can trust, you can't always. You just have to trust your gut feeling," Ally said.

CBS News could not reach coach Williams for comment.

The American Association of Cheerleading Coaches and Administrators says it has viewed the videos and "does not condone the coach's actions, and rejects them to the fullest extent."