Pakistan is all too familiar with sectarian violence, but the massacre in Quetta's Ishnam Asheri mosque, the worst act of its kind since the mid-'90s, was horrifying even by South Asia's gruesome standards. Thousands of worshipers were performing their Friday prayers when two gunmen burst in and fired into the crowd for 10 minutes, pausing only to reload. Outside the mosque, a third man, wired with explosives, walked into a cluster of worshipers and blew himself up. By the time police dispatched the gunmen, 47 people were dead and 65 wounded. Police defused two more bombs that could have killed hundreds more. Suspicion quickly fell on an offshoot of the banned Sunni radical group, Sipah-e-Sabah, whose preachers denounce Shi'ites as infidels and whose members have been accused of murdering Shi'ite doctors and lawyers. Police also believe that this group helped al-Qaeda carry out two suicide bombings last year in Karachi—on May 8 against a bus carrying French naval technicians, and on June 8 against the U.S. consulate.