PENNSBURG, Pa. — A man suspected of going to three houses in the Philadelphia suburbs and fatally shooting six people, including his ex-wife and her teenage niece, was at large, and prosecutors said investigators didn't know where he was or how he was getting around. Police recovered the cellphone and car of Bradley William Stone, who had recently been in court fighting with his ex-wife over custody of their two children. SWAT teams surrounded his Pennsburg home on Monday and pleaded through a bullhorn for him to surrender, but Montgomery County District Attorney Risa Vetri Ferman said it was unclear if he was there.