Last night's suicide bombing at a concert by American pop star Ariana Grande killed at least 22 people and hospitalized 59 more in Manchester, England. Condolences are pouring in from all over the world. Chief Constable Ian Hopkins told reporters, "The man suspected of carrying out last night's atrocities is 22-yr old Salman Abedi…. Our priority is to continue to establish if he was acting alone or as part of a wider network." ISIS has claimed responsibility for the attack. Rukmini Callimachi reports on terrorism for the New York Times, focusing on ISIS and al-Qaeda.