Oscar Grant's Shot in Back by Police, Sue for 25 Million

Relatives of a man who claim he was shot in the back and killed by a policeman while lying unarmed on the ground are suing the officer's employers for $25m.

The shooting of Oscar Grant, 22, early on New Year's Day at a busy train station in Oakland, California, sparked widespread outrage. The incident was caught on video by at least three witnesses.

Footage shows Bay Area Rapid Transit police officers responding to a call about two groups of men fighting on a train around 2am on January 1. The officers put several of the young men on the ground against a wall on the station platform.

Mr Grant, who was travelling home after celebrating New Year's Eve in San Francisco, can be seen rising to his knees before being pushed back down by police. According to local television news reports, at least one of the home videos shows an officer putting his knee on Mr Grant before a colleague draws his gun and fires. Mr Grant, a butcher at an Oakland supermarket, died later that morning.

John Burris, a lawyer for the man's family, said Mr Grant, the father of a four-year-old girl, was lying on his stomach and posed no threat when he was shot. He said he would ask prosecutors to press criminal charges against the officer, who is on administrative leave.

"The officer leaned (in), was straddling over him and pointed his gun directly into the backside and shot (Grant)," said Mr Burris, one of Rodney King's lawyers in his 1994 civil suit against the Los Angeles Police Department. "This was not a deadly force situation."

In the claim, the officer who carried out the shooting is accused of having "mercilessly fired his weapon, mortally wounding Mr. Grant with a single gunshot wound to the back."

The document also states that Mr Grant "made a valiant effort to de-escalate the situation by appealing to the officer's sense of humanity by telling the officer that he had a four-year-old daughter" and asking the officer not to use a Taser gun on him.

The claim, the precursor to a wrongful death lawsuit, was sent to BART officials on Tuesday and alleges officers illegally detained Mr Grant, used excessive force and violated his civil rights. The authority has 45 days to respond. A spokesman said officials were reviewing the claim.

BART is meanwhile conducting its own investigation and has urged patience while the inquiry is carried out.

Linton Johnson, a BART spokesman, told local station KTVU-TV that authorities were trying to determine whether the officer who shot Mr Grant was actually reaching for his Taser gun and pulled out his handgun by accident.

News of the claim came as California?s attorney general, Jerry Brown, called for a "searching inquiry and investigation" into the shooting.

Interviewed by local television news station ABC7, he described amateur videos of the incident as "disturbing" and said there should not be "any kind of delay or shilly-shallying around" in dealing with the case.

Mr Grant's funeral was due to take place on Wednesday.