WASHINGTON (AP) — Bombings in New York and New Jersey — and a stabbing attack in Minnesota the same day — underscore that homegrown attacks inspired by violent extremists are as much a threat to the United States as those directed by terrorists, the nation's Homeland Security chief says. In prepared testimony before a Senate committee Tuesday, Johnson said air strikes and special operations against the so-called Islamic State terror group have led to the deaths of a number of its leaders. "In all, Islamic extremist terrorist have killed 63 people on U.S.