FORT LAUDERDALE, Fla. (AP) — Police nationwide are facing a heightened danger: Criminals are using home surveillance cameras to monitor their movements. The FBI believes that may have happened this week when two of its agents were gunned down by a child pornography suspect in South Florida. Authorities are investigating whether the suspect used a surveillance camera in his doorbell to spot the agents as they prepared to search his apartment and computer. He opened fire through the front door with a high-powered rifle as they approached, killing agents Laura Schwartzenberger and Daniel Alfin. Three other agents were wounded. The suspect killed himself.