It's been more than nine months since the tragic death of city Police Officer William H. Torbit Jr., who was killed by friendly fire from fellow officers in January as he tried to disperse an unruly crowd outside a downtown night club, and the public is still waiting for answers.

Mayor Stephanie Rawlings-Blake promised a prompt, independent investigation of the shooting, which claimed the life of an unarmed civilian and wounded several other people in addition to ending Officer Torbit's life. But that inquiry has been bogged down for months, in part by the unwillingness of officers who witnessed and participated in the incident to testify, apparently for fear they could open themselves to disciplinary action by the police department's internal affairs unit.

While we respect the officers' right not to provide testimony that could be incriminating, their refusal to cooperate with the mayor's panel in a timely fashion makes it appear they are more concerned with protecting their careers than helping the department avoid similar tragedies in the future. City officials need to figure out a way to break this bureaucratic and legal logjam, not only so the public can finally have a full and unbiased accounting of the events leading up to Officer Torbit's death but also so the department can take whatever steps are necessary to ensure such a nightmare isn't repeated.

Mr. Torbit, who was on duty but dressed in plain clothes the evening he was killed, was responding to a report of an officer in distress when he arrived at the Select Lounge nightclub on North Paca Street. There he encountered a large mass of people spilling out onto the street; he was struggling to persuade them to leave the area when he was assaulted by members of the crowd and thrown to the ground, where the badge he was wearing around his neck became dislodged.

By then, other officers were converging on what had turned into a chaotic scene, unaware that Mr. Torbit was already in the midst of it and engaged in a scuffle. When Mr. Torbit reached for his service weapon to defend himself against his assailants, his colleagues apparently mistook him for a threat and loosed a fusillade of dozens of bullets, killing him.

The shooting immediately raised questions about the appropriateness of the police response. By the time the bullets stopped flying, Sean Gamble, an unarmed man with no criminal record, had also been killed, and three female bystanders, as well as another police officer, were left wounded. Among the many issues raised by incident were whether officers are adequately trained to handle such situations, whether the department should revise its policies on the use of plainclothes officers and whether the officers who participated in the shooting used good judgment in firing so many shots, which one witness claimed were aimed almost directly into the crowd.

Last month, Baltimore City State's Attorney Gregg Bernstein cleared those officers of criminal misconduct, concluding that the deaths of Mr. Torbit and Mr. Gamble and the wounds suffered by the other victims ultimately were the result of a tragic accident stemming from a chain of well-intentioned but poor decisions by officers on the scene.

Only after the criminal case was closed was the police department able to begin its internal review of the incident. It's going on now, and that's why on Monday officers involved in the shooting refused for the second time this year to talk to the mayor's panel.

Now is the time for Police Commissioner Frederick H. Bealefeld III and Mayor Rawlings-Blake to step in. Either the department's internal affairs unit should expedite its inquiry so the threat of disciplinary action is no longer hanging over the officers' heads, or the department should grant them some form of immunity so that whatever they say to the panel can't later be used against them by internal affairs. That's not an ideal solution, but it's necessary to ensure the safety of Baltimore's police officers and residents alike.