Authorities in the Britain believe a suicide bomber was behind a possible explosion at an Ariana Grande concert at Manchester Arena. NBC News reports that U.K. authorities told American officials that they suspect a suicide bomber detonated a backpack bomb toward the end of the concert. At least 20 people are reportedly dead, with dozens of others hurt. There are reports of people with injuries that could have been caused by shrapnel from an explosive device. Bomb squads and emergency crews are on the scene.