BENI, Congo—An Islamic leader in Congo’s eastern town of Beni was killed during evening prayers by unidentified gunmen after days of violent attacks by rebels left at least 19 people dead, officials said. Gunmen came into Beni’s central mosque Saturday, shooting dead Sheikh Ali Amin Uthman, the representative of the Islamic community of Beni, according to the head of the mosque, Sheikh Moustapha Matsongani. The identity of the attackers was not yet known. Matsongani told The Associated Press that Amin had been receiving threats from the Allied Democratic Forces (ADF) for more than a year, and had been questioned by security services days earlier about those threats. “We asked him to leave Beni if possible to flee the death threats,” said the governor of the North Kivu province, Nzanzu Carly Kasivita. “Investigations are underway.” Amin had often gone on the radio to denounce extremism. His attack came on the heels …