The officers fired 50 bullets, killing Sean Bell and injuring two friends as they drove away from the club.

The detectives were investigating alleged prostitution at the Kalua club.

The verdict triggered cries of protest in and outside the courtroom after a trial that has gripped the city's media for seven weeks.

"There is no justice in America," cried one man outside the courthouse after the verdict. Among those who walked out in protest were Mr Bell's parents and the civil rights activist the Reverend Al Sharpton.

The defendants – detectives Gescard Isnora, Michael Oliver and Marc Cooper – waived the right to a jury arguing that any panel would be biased against them because of the publicity surrounding the case. Charges against them included first- and second-degree manslaughter.

However, Judge Arthur Cooperman said the prosecution had failed to prove that the officers had over-reached their authority in firing the shots. " The testimony of those witnesses just didn't make sense," he said.