May 11, 2026 / 9:07 AM EDT / CBS News Add CBS News on Google Sean Gardner, a gymnastics coach who trained elite young girls, will be in federal court in Mississippi on Monday for a change of plea hearing after facing 12 felony counts of sexual exploitation of children. He initially pleaded not guilty.  The charges stem from allegations Gardner set up a hidden camera in a girls' bathroom in a Purvis, Mississippi, gymnastics facility where he worked, recording girls between the ages of about 6 to 14 undressing and changing into their leotards in 2017 and 2018. Investigators seized approximately 50 videos and 400 photos from Gardner's residence as evidence, according to an FBI affidavit. Gardner is allegedly seen shutting the camera off in one of the videos. In addition to those allegations against Gardner in Mississippi, there are also claims of misconduct at one of the most revered gyms in competitive gymnastics.…