BERTHY Loupatty, leader of the notorious Cowok Keren gang in Ambon, was incensed. Pointing a blue pen at presiding judge Arwan Byrin of the North Jakarta District Court, he shouted in anger: "They beat me and forced me to sign a blank piece of paper!" Berthy was replying to a question by the judge whether he had signed the police report implicating him in a series of violence in Ambon. He named Adj. Insp. J.H. Latuheru, of the Maluk