FLINT, Mich. (AP) — Authorities are investigating a report that a girl at the Alternative Path Academy was sexually assaulted by three boys at the Flint school.

MLive.com reports (http://bit.ly/12qlu9u ) Friday that principal Fred Williamson confirms the incident took place at the school for students aged 12 to 17.

The incident was reported Thursday to police. A police report states the girl was sexually assaulted by two boys who tried to get her to have sex with them. Another boy asked the girl in a letter for sex.

She was threatened by one of the boys and told not to tell.

The alternative school opened in October.