Twenty-one-year-old Christopher Bostick is being held on $250,000 bond after he allegedly sexually assaulted a 7-year-old boy who he was supposed to be mentoring.

Police say Bostick has been charged with rape.

He met the young boy through Big Brothers Big Sisters of Memphis, an area mentoring program. Bostick is a counselor there.

"Big Brothers Big Sisters of Memphis is aware of the child abuse investigation of a former volunteer in our program and are alarmed and deeply saddened by reports of any child being harmed," said Adrienne Leslie Bailey, president and CEO, in a statement. "We are working proactively with law enforcement and are unable to provide further details or speculation beyond this written statement."

"Big Brothers Big Sisters is a recognized leader in child safety. We make child safety our priority and have zero tolerance for abuse of any kind. We have been a leader in providing child safety education to mentees and their families based on effective prevention practices developed by nationwide experts. We remain committed to improving children's odds for succeeding in school and breaking negative cycles and believe that safety and security are the foundation of the service we provide. The integrity of our program is extremely important and to achieve the highest quality standards possible, we work to constantly review and strengthen our screening and background check systems as new best practices in the industry emerge."