For months, the FBI and the New York police department had been keeping a close eye on 24-year-old Najibullah Zazi, a Denver man suspected of hatching a bomb plot on U.S. soil. As part of their investigation, detectives enlisted the help of Ahmad Wais Afzali, a Queens imam who knew Zazi. But hours after being interviewed, the so-called informant allegedly turned around and phoned Zazi, warning him that the cops were watching. The betrayal forced authorities to launch a series of raids and arrest a handful of suspects earlier than planned. Federal prosecutors have now charged Afzali with lying to the FBI.