The unarmed man killed by former BART police Officer Johannes Mehserle on an Oakland train platform early New Year's Day put up a brief struggle with officers but had been restrained and had both arms behind him when he was shot in the back, police investigators said. The conclusion by Oakland police, contained in a legal filing made public Wednesday, contributed to Alameda County prosecutors' decision to charge Mehserle, 27, with murdering 22-year-old Oscar Grant of Hayward. It was an extraordinary decision. Several legal experts said they could recall no instance of a police officer in California being charged with...