KUALA LUMPUR (Reuters) - Former Malaysian prime minister Najib Razak asked a U.S. court on Tuesday for permission to seek documents and testimony from investment bank Goldman Sachs to help in his defence against criminal charges in Malaysia over the 1MDB financial scandal. Najib, who is on bail after being sentenced to 12 years in jail in July on charges of corruption and money laundering, is expected to appeal the conviction in February and faces four more trials related to the scandal. The U.S. Justice Department has said about $4.5 billion was misappropriated from state fund 1Malaysia Development Berhad (1MDB), which Najib co-founded in 2009, including some funds Goldman had helped raise for the firm.