A federal grand jury here today charged six police detectives and one former detective with violating the constitutional rights of black citizens they were questioning in connection with last year's slaying of one of their fellow officers.

"The officers handcuffed and tied persons in their custody to a chair, struck them over the head with a large book, struck them in the chest with their fists and 'bagged' them," the indictment said. "Bagging" refers to the practice of putting a plastic bag over a person's head, the indictment said.

The interrogations resulted from the Nov. 8 shooting of Patrolman Gregory Neupert in Algiers, across the Mississippi River from downtown New Orleans. The murder touched off an intense police investigation in that part of the city centering on the all-black Fischer housing project there.

During the inquiry, police killed four people, including three who died Nov. 13 in two pre-dawn raids.

Two of those killed Nov. 13 were suspects in Neupert's slaying police spokesmen said then. Neupert was white, the four killed were black.

These killings and reports of alleged police brutality touched off demonstrations and attempts by blacks to get people to boycott downtown merchants.

After an intensive investigation, an Orleans parish (county) grand jury said in May that it did not have enough evidence to indict any policemen on brutality charges. That announcement touched off more protests and demonstrations, culminating in a two-day sit-in last month in Mayor Ernest N. Morial's office. No arrests were made in connection with those incidents.

The day the Orleans parish grand jury made that report, Orleans parish district attorney Harry Connick said policemen probably did violate Algiers residents' civil rights during the Neupert investigation. However, he said, many who claimed they were beaten did not want to testify or were too vague to warrant indictments.

On June 11 Stephen Reboul, 28, a seven year police veteran, was dismissed from the force, allegedly in connection with his involvement in the Algiers case.

In its May report, the grand jury had left open the question of whether Reboul should be charged in connection with the death of a woman shot during one of the November 13 raids.Police had said she was shot because she pulled a gun on officers in the house.

Today, Reboul was charged with one midsemeanor count in connection with the Neupert investigation.

Charges against the other six were misdemeanors, too.Others indicted and the charges against them:

Sgt. John E. McKenzie, 39, a 12-year veteran, two counts.

Dale Bonura, 33, another 12-year veteran, three counts.

Stephen Farrar, 30, a six-year policeman, two counts.

Ronald F. Brink, 34, a 13-year policeman, two counts.

Thomas R. Woodall, 31, an 11-year policeman, two counts.

Richard LeBlanc, 31, an 11-year police veteran, two counts.

The federal grand jury had been expected to report Wednesday, but its work hit a snag when Connick refused to let his investigators testify before the panel.