The transit police officer who shot and killed an unarmed black man on New Year's Day has pleaded not guilty to murder.
Johannes Mehserle entered the plea Thursday in a packed Alameda County courtroom with supporters and family members of both the officer and the victim, 22-year-old Oscar Grant.
Prosecutors say Mehserle was standing over Grant, who was lying facedown and restrained on a train platform, when the Bay Area Rapid Transit officer fired one shot into the man's back.
Cell phone videos of the shooting have gone viral on the Internet, sparking outrage by many Oakland residents and African American community leaders.
The shooting at the Fruitvale station in Oakland occurred shortly after 2 a.m. on Jan. 1 when Mehserle and other officers stopped a train at the station in Oakland after receiving reports that two groups of men were fighting on board.
The shooting, which is under investigation by multiple agencies, has prompted protests in the Bay Area, including a violent demonstration last week in Oakland.
The Alameda County District Attorney's Office has filed murder charges against Mehserle.
A Bay Area man came forward this week alleging that he was beaten up by Mehserle. He said the officer was arrogant and "thought he could not be touched because he had a badge."
Carrethers told CNN on Thursday that he got off the BART train with a woman when he made a comment about officers being lazy.
"I was having a conversation with another passenger (and) I stated to another passenger you see that's why they stand around with their hands in their pockets," he said.
But a police report said that Carrethers was abusive towards the officers and they feared he was going to strike one of them. Carrethers refuted the report.
"The police officers that night seemed to have an attitude," he said. "I was beaten up because I didn't agree with them...Another officer came up and got in my face and said I think you're drunk."
The police report said that the officers only grabbed Carrethers left arm after he became abusive. Mehserle's attorney said Carrethers allegations against his client are false.
"The allegations are ridiculous and they didn't occur," Mehserle's attorney Christopher Miller said in a statement. "We question the timing of the allegations of Mr. Carrethars to come forward at this time."
But Carrethars said he came forward shortly after the incident but no one listened to him.
"I've been trying to get help for the longest," he said. "And I truly believe had someone listened to me at the time I tried to get help I think Oscar Grant might still be alive.
The former BART police officer was due to appear in an Oakland court Thursday afternoon. After spending the night in an Alameda County jail, Mehserle was scheduled to be arraigned at 2 p.m.
Mehserle was extradited from Nevada on Wednesday and he spent the night in Santa Rita Jail in Dublin.