In the summer of 2006, an FBI official visited a mosque in Orange County, California. His intention was to reassure the community that they weren’t being spied on. But a few months later, an undercover informant named Craig Monteilh showed up at the mosque. Monteilh says he’d been sent there to catch terrorists. But his behavior was so odd that Monteilh himself came under suspicion. Documentary filmmaker Sam Black reports the story. (25 minutes)