He was suspected of training the five suspects on how to handle police questioning, officers believed.
Some lawyers who have handled police brutality cases said the department was reluctant to order a full-scale investigation of such cases.
Transit and police officials are close to agreement on how to handle police requests to halt subway trains so officers can search for fleeing criminals.
Lt. Col. Dawoon al-Sahin of the local police said he believed that the bomb may have been aimed at one of the slain officers, Lt. Col. Hussein al-Qaisi, who handled police personnel issues.
"Even if he was stealing paving stones, the penalty for stealing paving stones is not death," said Sanford A. Rubenstein, a prominent lawyer who handles police brutality cases and is representing the family along with Jay H. Schwitzman.
And Donald W. Cook, a lawyer who handles police abuse cases in Los Angeles, pointed to another potential problem: when a person is wrongfully arrested on a warrant, the real suspect "gets a free pass" as the warrant is removed from the system.
Speaking at a Congregational church in Queens, Norman Siegel, executive director of the New York Civil Liberties Union, said the verdict highlighted the need for a permanent special prosecutor to handle police brutality cases, among other reforms to investigate and prevent police misconduct.
Neither Mrs. Clinton nor Mr. Lazio, he said, had spoken specifically on whether, for instance, they supported calls for federal oversight of the New York Police Department or a special prosecutor to handle police brutality complaints.
Lieutenant Pigott, a decorated officer with six years in the Emergency Services Unit, was put on modified duty and ordered to work the desk at Fleet Services, which handles police vehicles, in Queens.
