NEW YORK (AP) _ The cheering began as the parents of Amadou Diallo left the prosecutor's office.

Black bystanders fell in behind the couple Wednesday as they marched two blocks to a courthouse where four white police officers pleaded innocent to murder charges in the shooting death of the Diallos' son, a 22-year-old street vendor from Guinea with no criminal record.

The officers heard cheers, too _ from scores of their off-duty colleagues, most of them white.

``On Feb. 4, in the vestibule in his own building, Amadou Diallo stood blameless, unarmed and defenseless when 19 of 41 shots were fired at him, struck him and killed him,'' prosecutor Robert Johnson told the court. ``These four defendants intended to take his life.''

The case _ a searing mix of racial politics and alleged depravity _ has inspired a painful examination of police attitudes and tactics across the nation. Earlier this month, President Clinton said he was worried that recent charges of police misconduct could undermine the fight against crime.

More than 1,200 people have been arrested in the city in demonstrations since Diallo was cut down in the fusillade. Many of the protesters _ white and black, celebrities and common folk _ also demonstrated against the alleged police torture of Haitian immigrant Abner Louima in 1997 and the feeling that law-abiding minorities are routinely humiliated by police stop-and-search tactics.

``Amadou's blood will feed the battle for justice,'' his mother, Kadiadou Diallo, told 1,000 supporters outside the courthouse.

The killing has frayed Mayor Rudolph Giuliani's already tense relationship with New York's black community. Many have accused him of failing to understand the depth of New Yorkers' anger over the incident.

Giuliani declined to comment on the charges, but said earlier in the day: ``We should allow the criminal justice system to now operate. ... Now you move to another stage in which the crime has to be proved beyond a reasonable doubt.''

Officers Kenneth Boss, Sean Carroll, Edward McMellon and Richard Murphy _ who were searching for a rape suspect and fired apparently believing Diallo had a gun _ showed little emotion when the charges were read.

Each was indicted on two counts of second-degree murder and one count of reckless endangerment. They could get 25 years to life in prison on the murder charges.

Judge John Collins set bail at $100,000 for each officer, although Johnson had asked that they be held without bail. The officers were immediately suspended from the force. They had been on desk duty.

Marvyn Kornberg, Carroll's lawyer, called the murder count ``ludicrous.''

``What's the district attorney saying, that they had nothing to do that night but roll up on an individual and attempt to kill him because he's black?'' he asked.

Lawyers for the four officers spoke separately in court, offering the first glimpse of the defense account of what went wrong the night they confronted Diallo outside his Bronx apartment building.

James Culleton, Murphy's lawyer, said his client ``had a sick feeling inside of him, believing that he was going to be shot, and he reacted.''

Culleton and Steven Brounstein, Boss's attorney, said their clients fired because they saw an officer on the ground. McMellon reportedly slipped and fell as the officers confronted Diallo.

Boss ``believed there was a fire fight was going on,'' Brounstein said.

At a news conference, Johnson criticized the officers for choosing not to testify before the grand jury which voted last week to indict them.

``Having exercised that right, they cannot then say, `We're police officers, therefore what we did was OK,''' he said.

``Without explanation, what we have is four people driving up to a location, pulling out their guns and killing an individual.''

The Rev. Al Sharpton, who organized daily protests against the shooting, praised the grand jury's action.

``We can only say that it is appropriate that these policemen have been indicted for murder,'' he said. Diallo's father would only say, ``I'm very happy.''

Since the shooting, New York's street-crime unit has been ordered to wear uniforms instead of plainclothes, and 50 slots at the predominantly white division will be reassigned to minority police officers.

Earlier Wednesday, Giuliani and Police Commissioner Howard Safir attended an emotional tribute to a cop killed in the line of duty in 1996. Safir called Diallo's death a tragedy but urged NYPD critics to ``acknowledge the tragedies that befall our family.''

``We grieve for Amadou Diallo and the four officers involved and pray they get a fair trial,'' Safir said.