A man in Boston being followed by the FBI’s Joint Terrorism Task Force was shot and killed by law-enforcement officials Tuesday as he approached them with a “military-style” knife or machete. The FBI had tracked 26-year-old Usaama Rahim for several weeks before he allegedly "came at the officers" with the weapon in a CVS parking lot. “Our officers tried their best to get him to put down the knife,’’ Boston’s police commissioner said. “Unfortunately, they had to take a life.’’ Police reportedly wanted to question Rahim "about his intentions in some other matters that we turned up." Authorities are also reportedly looking into whether Rahim was radicalized by ISIS propaganda online.