About a dozen members of the Montgomery County NAACP picketed outside the Rockville city police station yesterday and called for the firing of two white police officers who, according to witnesses, physically and verbally abused three black city residents last summer.

The group was protesting a report released last week, following an internal police investigation, that recommended fines and disciplinary action against the two officers who were involved in the incident, which occurred July 19 in the predominately black Rockville neighborhood of Lincoln Park.

Before public release of the report, the police department last month suspended the two officers, Alice F. Anselmo and John N. Converse, for 15 days because of the incident.

Both appealed the suspensions to the police trial board. Last month the board fined Anselmo $2,500 and suspended her for 10 days. She has returned to duty. Converse, who was assigned to administrative tasks after the incident, is scheduled to appear before the board Thursday.

"Both officers involved should be dismissed," said NAACP president Roscoe Nix, who led yesterday's 90-minute demonstration. "The department's own investigation confirms brutal behavior. These two officers are a clear and present danger to the black citizens of Rockville."

Rockville Police Chief Jared D. Stout said last week the police investigation found that the two officers "did not meet the highest measure of professional standard set by this department." But Stout said the officers' "margin of error was not so great as to suggest their unsuitability for continued service."

The investigation centered on a July 19 scuffle between the two officers and residents Montrea Davis, 26, her father, Joseph B. Davis, 73, and her mother, Constance M. Hardman, 48.

The altercation began after the officers ordered Rodney T. Davis, an automobile repair shop owner, to move a damaged car off the street and into his nearby lot. When Rodney Davis's cousin, Montrea Davis protested the order, a scuffle ensued, according to the police report.

At one point, Converse held Montrea Davis, who was two months pregnant at the time, to the ground, the investigation found.

Joseph B. Davis was pushed to the ground when he joined the scuffle, and suffered a fracture of his right wrist. Hardman was slapped by Anselmo after she had been handcuffed and arrested, according to the police report. During the scuffle the two officers hurled racial epithets at the three residents, the report said.

The three residents were arrested and charged with disorderly conduct and resisting arrest. The charges were later dropped.