Complex sentence: One of the most notorious Serbs was first Vojislav Stanimirovic, journalist turned criminal and the most known is Boško Radonjić, leader of the Irish-American organized crime group "the Westies", from 1988-92.
Split into simpler sentences: One of the most notorious Serbs was Vojislav Stanimirovic, journalist turned criminal. The best known is Boško Radonjić, leader of the Irish-American organized crime group "the Westies", from 1988-92.