SAN FRANCISCO (AP) - A former California transit officer who fatally shot an unarmed man on an Oakland train platform in 2009 has asked an appeals court to overturn his conviction.

      A lawyer for Johannes Mehserle argued Wednesday that the shooting death of 22-year-old Oscar Grant was a tragic mistake but not involuntary manslaughter.

      Attorney Dylan Schaffer is asking the California Court of Appeal to toss out the conviction against the former Bay Area Rapid Transit officer.

      Mehserle has maintained that he meant to use his Taser but accidentally grabbed his gun when he shot Grant, who was lying face down on the platform early on New Year's Day.

      Assistant Attorney General Gerald Engler argued that Mehserle's numerous mistakes and bad decisions that morning amounted to gross negligence and added up to involuntary manslaughter.

      
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