NEW YORK (AP) _ More than 8,000 police - a third of the city's force - angrily demonstrated outside a courthouse Thursday, protesting the indictment of a fellow officer who killed an elderly woman during an eviction proceeding.

''If Stephen Sullivan is indicted, we all stand indicted,'' Phil Caruso, president of the Patrolmen's Benevolent Association, told the crowd. ''We are asking for simple justice: Police Officer Sullivan must be exonerated.''

Department spokesman Sgt. Peter Sweeney said it appeared to be the largest police demonstration since a 1976 contract dispute. The officers, in street clothes, ringed the state Supreme Court building near Yankee Stadium in the Bronx, then gathered 40-deep on a nearby plaza.

They chanted and hoisted banners condemning Bronx District Attorney Mario Merola, whose office presented the case to the grand jury that indicted Sullivan last week. ''Mario must go 3/8'' and ''Merola the Ayatollah 3/8'' the officers yelled, waving clenched fists in the 28-degree cold.

Inside the building, which houses Merola's offices, an aide later issued a one-sentence statement: ''They have a perfect right to demonstrate.''

Sullivan, a member of the elite Emergency Services unit, was charged with manslaughter in the shotgun killing of Eleanor Bumpurs, 66, last October. The woman, who had a history of emotional problems, was being evicted from her apartment for nonpayment of rent, and police say she lunged at an officer with a knife.

Caruso said police believe Sullivan was a scapegoat for society's failure to help people such as Mrs. Bumpurs.

''We're very upset. Now we don't know when to use our force, because we're being second-guessed by everybody,'' said a protesting officer who declined to give his name. ''It makes it very difficult to do your job.''

The rally intensified a week of police outcry. Caruso said all Emergency Services officers will seek transfers to other posts, and some officers have begun asking for prosecutors to be present before they make difficult arrests.

The PBA will ''just play from day to day'' in coordinating further protests, Caruso said. But when police began chanting, ''No support, no work,'' he spoke against major disruptions in service.

''We are going to do our jobs,'' he said. ''We're not going to turn our backs on the people - because they won't turn their backs on us.''

The officers at one point turned their anger away from Merola to question the absence of police Commissioner Benjamin Ward, who has remained silent about the ongoing police protests and issued no statement about the rally.

After the indictment, Ward limited the use of shotguns and announced plans to buy electric weapons to stun emotionally disturbed people. He also lifted Sullivan's badge and gun and transferred him to a desk job.

Sullivan, a 19-year veteran of the force, was at work Thursday and did not attend the rally.

His lawyer, Bruce Smirti, said he filed motions Thursday asking to have the indictment dismissed as legally insufficient or at least to have the case moved out of the Bronx.