A Calgary school librarian has been charged with sexual assault for allegedly having a sexual relationship with a 15-year-old boy.

CTV has learned that 48-year-old Agnes Kooy is facing charges.

Police confirmed the alleged incidents with the teen took place over a six-month period earlier this year.

Kooy was charged in August after the boy's parents and the school became suspicious about the pair's behaviour.

Police said they didn't go public about this news until now because there was no danger to the public.

They added they believe this was an isolated incident and that there wasn't any predatory action.

Police allege that this was a relationship though the boy is not old enough to legally consent.

Kooy has been removed from the school but the school board won't say if she's been suspended with or without pay or if she's been let go altogether.

Police said Kooy was ordered not to contact the boy when she was first arrested and released.

But she allegedly contacted the teen and was thrown back in jail.

She is free again but no longer living at home.

Police also said the boy, now 16, is not cooperating with police.

Kooy is due back in court in November.