The Manhattan district attorney, Robert M. Morgenthau, said his office was investigating the shooting and that the case would be presented to a grand jury. But he cautioned that it was standard procedure to bring all police shootings before a grand jury, except in very few cases in which it is clear that the shooting was justified.

Image Omar J. Edwards

“Whenever there’s any question about justification, it goes to the grand jury,” Mr. Morgenthau said.

The shooting has once again raised questions about departmental procedures involving communications among plainclothes officers  particularly those in different units  as well as issues of race.

Officer Edwards was black, and Officer Dunton is white.

The Rev. Al Sharpton said on Friday that he was “concerned of a growing pattern of black officers being killed with the assumption that they are the criminals.”

“This calls for federal investigation and intervention to sort out the facts and bring about a just resolve,” Mr. Sharpton said. “Can police investigate themselves fairly and impartially? It would seem very difficult at best and unlikely in fact.”

Mayor Bloomberg said on his morning radio show that investigators were reviewing security tapes of the shooting, which he maintained was not deliberate, and interviewing witnesses. Investigators were also questioning the man Officer Edwards had been chasing.

"The only thing that can come out of this is to improve procedures so perhaps it doesn’t happen again," the mayor said. "We all know policing is a dangerous job and accidents happen when people have guns in their hands, even legal guns in this case which they are authorized and trained to use."