Before he strapped on his suicide vest, walked into a crowded police station mosque and blew himself up last month, Muhammad Syarif was typical of the scores of angry young men who pass their days at fundamentalist mosques in this coastal Javanese city.Mr. Syarif, 31, was a familiar face at often-violent protests, organized by local clerics, against alleged places of immorality, like karaoke bars and unregistered Christian churches. Last year, he joined mobs wielding sticks, staves and machetes who clashed with members of Ahmadiyya, a minority Muslim sect deemed heretical by fundamentalists.
But to the police, Mr. Syarif was of little interest. Like many members of a small and vocal fringe of Islamist vigilante groups in Cirebon, Mr. Syarif operated with near-impunity as the local authorities turned a blind eye to — or even tacitly condoned, liberal Muslim leaders say — an atmosphere of ...