Two men arrested over a stabbing committed by someone else during a street fight have been cleared of murder charges brought under a rarely-used legal principle.

The jury in Fairfield, southern California, rejected prosecutors' efforts to hold Justin Pacheco and David Moreno responsible for the death of their friend Jerry English under the the provocative act law.

The three men had fought on the same side in a 1997 brawl between two groups of teenagers.

Someone on the other side, Chad O'Connell, stabbed Mr English, but prosecutors decided Mr O'Connell acted in self-defence.

Instead Mr Moreno and Mr Pacheco were charged under the provocative act rule, which allows instigators of fights that end in a death to be charged with murder.

As the verdict was read, family members cried, hugged and made the sign of the cross.

"Finally, 12 people have brains. It's justice. Now everyone will know they're innocent," Mr Pacheco's mother said, wiping away tears.

The judge ordered the two men to be released after nearly 2½ years in jail.

"It's a wonderful vindication of common sense, and that's what a jury is supposed to do," said Gerald Uelmen, a law professor at Santa Clara University.

'Singled out'

He said the verdict "will certainly give prosecutors second thoughts" about invoking the provocative act rule.

Civil rights groups had said that Mr Moreno and Mr Pacheco, now both 21, were singled out by prosecutors because they were the only Hispanics among the nine people in the fight.

Human rights activists have demanded an investigation of the prosecutors' office, claiming the trial was racially motivated.

They are calling for a thorough investigation of cases brought by local prosecutors, to see if others bear racial overtones.

The provocative act rule, observed in Maryland and California, has been used only a few times in the past couple of years.

Some defence attorneys say it is being abused as a tool against gang-related crime.

Street brawl

The brawl stemmed from a series of put-downs and fights between the two groups of teenagers. The previous night, the two groups had scuffled, and a window had been broken on Moreno's car.

The next day, according to prosecutors, Mr English, Mr Moreno and Mr Pacheco went looking for Mr O'Connell and his friends.

They spotted them and got out of their car swinging pipes and clubs, prosecutors said.

Mr O'Connell, then 16, stabbed the 17-year-old Mr English.

Weeks after Mr Moreno and Mr Pacheco were charged with murder, a judge said the case had no merit and threw it out. But another judge overruled the dismissal.

A jury convicted the two young men, but the verdict was thrown out after several female jurors said they had been browbeaten by male jurors into voting guilty.