A judge ruled Thursday that a former transit police officer should stand trial on murder charges in the fatal shooting of an unarmed man on a train platform.

Alameda County Superior Court Judge Don Clay said there was sufficient evidence for ex-Bay Area Rapid Transit police officer Johannes Mehserle to face murder charges in the shooting of Oscar Grant early New Year's Day.

"There is no doubt in my mind Mr. Mehserle meant to shoot Oscar Grant with a gun, not a Taser," the judge said.

Mehserle's defense has contended that Mehserle accidentally grabbed his pistol instead of his stun gun when he shot Grant, who was face down on the platform.

Mehserle has pleaded not guilty.

When the judge rendered his decision, Mehserle sat looking straight ahead. Grant's mother, Wanda Johnson, burst into tears.

During several days of a preliminary hearing, the prosecution and Mehserle's attorney called witnesses and presented evidence in the controversial video-recorded shooting that prompted sometimes violent protests in Oakland.