DHAKA, Bangladesh (AP) — A former Bangladeshi Islamist party leader, whose imprisonment on war crimes charges triggered violent protests last year, has died of a heart attack in a prison cell of a government hospital. A special tribunal last year sentenced Azam, a former chief of Jamaat-e-Islami party, to 90 years in prison on 61 charges of war crimes during the Bangladesh 1971 war of independence from Pakistan. Prime Minister Sheikh Hasina, who set up the tribunal in 2010, says she had pledged before the 2008 election — which her party won in a landslide — to prosecute those responsible for war crimes.