Broward Sheriff's Office Carl Lechner, 66, was already facing child porn charges when sickening new allegations involving a now 21-year-old victim emerged.A children's gymnastics coach is behind bars in south Florida while accused of repeatedly sexually assaulting a girl as she was locked in a downstairs room a little more than 10 years ago.Carl Lechner, 66, was already facing charges for possessing child porn after his July 31 arrest when the sickening allegations involving a now 21-year-old victim emerged.The woman told Broward County detectives that she was sexually assaulted about 10 times over the course of four years by Lechner when she visited his home to play with his children between 1999 and 2003.The abuse was detailed in a complaint against Lechner in 2004 but it wasn't until his recent arrest that detectives say they became aware of the allegations, leading to additional charges filed against him on Monday.