Harry learns that his parents were sold out to Lord Voldemort by their friend Peter Pettigrew , also accused of framing Harry 's godfather Sirius Black for crimes he did n't make , locking him up in the wizarding prison , Azkaban . Harry learns that his parents were betrayed to Voldemort by their friend Peter Pettigrew , who framed Harry 's godfather Sirius Black for the crimes , condemning him to Azkaban , the wizard prison .