>>2477410OP is retarded.
>get involved with PTA/volunteer>get regular access to building under premise of regularly donating books or toys bought on the cheap from garage sales/trade shows/goodwill/ebay>locate hidden room if it exists>investigate once for clues>later install hidden camera, film self installing it with your concerns, noting that you did not build this room or furnish it yourself>stream of conciousness narration for authenticity, stay as sane and coherent as possible>monitor schedule of room's activity>notify other parents but urge not to act>watch live if possible or during hot times to catch teacher in act with other parents, so multiple witnessesSpread your deniability and make sure you have active supporters from other parents. They can twist the story onto one conspiracy theory-riddled insane dad, but they can't pin it on 8 separate families running their own sting and putting the evidence online before the police can ever take existing copies and "lose" them
Always proceed at every step as if they were going to commit crimes on children and pin it on you; plan and react accordingly.