EDITORS PLEASE NOTE: THIS EDIT CONTAINS MATERIAL WHICH WAS ORIGINALLY 4:3<br/> <br />Although actor Philip Seymour Hoffman was found with a syringe in his arm, the cause of his death remains undetermined and more study is needed, according to New York City's Chief Medical Examiner .<br/> <br />Four people were arrested on Tuesday during a raid on a building in lower Manhattan after police traced what they believe to have been the source of the heroin suspected of killing the Oscar-winning actor.<br/> <br />Meanwhile, Hollywood continues to mourn of the loss of Hoffman, one of the leading actors of his generation<br/> <br />At the world premiere of "The Monuments Men," actor George Clooney said he was filled with both shock and sorrow upon hearing the news.<br/> <br />SOUNDBITE George Clooney saying (English):<br/> <br />"It's very difficult and very tricky to be here tonight in this town, you know, two days after he, you know, he's gone," said a subdued Clooney. "And you know, it's a very difficult time for everybo
