Johannes Mehserle is charged with fatally shooting Oscar Grant while he was handcuffed at the Fruitvale BART station on New Year's Day 2009.
An attorney for BART says depositions from Grant's friends, detained with him, say they heard Mehserle warn Grant he was going to Tase him. They also say Mehserle did not swear or display anger before shooting Grant.
Defense lawyers all along have claimed Mehserle shot Grant by mistake, thinking he was using his Taser.
