BALTIMORE — A cascade of mistakes by police officers breaking up a fight outside a Baltimore nightclub led to the tragic shooting deaths of a plainclothes officer and another man, the head of a panel reviewing the incident said Thursday.

“It provides a clear example of how the authority that police have to use lethal force can carry the heaviest of responsibilities and consequences,” said James K. “Chips” Stewart, the head of the Independent Review Board. “The IRB comprehensive review documents a number of mistakes that cascaded through the entire incident that ultimately resulted in the use of lethal force.”

Officer William Torbit Jr. was on duty in street clothes when he responded to a report of trouble at the Select Lounge on Jan. 9. Investigators say Torbit likely fired the bullet that killed Sean Gamble as he was stomped by a group of six to eight people. Not knowing that Torbit was an officer, uniformed officers fired 42 shots in six seconds, striking and killing Torbit and wounding four others, including a uniformed officer, according to the report.

Cardinal rules of policing were not followed and a lack of supervision and a disorganized response contributed to the chaotic situation, the report found. Among 33 recommendations in a 169-page report, the board suggests that the department develop a plan for responding to such situations and enforce the dispatch system to track where officers are.

The probe was hampered by the fact that the four officers who fired during the incident declined to answer the board’s questions. They provided only brief memos that left out a lot of details, leaving the report without important information, Stewart said. Those four officers are still assigned to administrative duties while an internal investigation proceeds.

“They were in a position to have knowledge of the facts and circumstances and their interpretation according to their training,” Stewart said. “When they weren’t able to give us that information we could only go on the videotapes, the physical evidence at the scene and the other witnesses who were standing with them.”

The report finds that the current training for crowd control doesn’t prepare officers to intervene in disorder at clubs. It recommends that training reflect realities such as responses to clubs, that supervisors follow protocol when responding to such events and the department train officers to prevent recurring problems at clubs.

Because the department doesn’t have oversight of promoters for clubs and bars, the panel recommends that the department seek to implement a permitting system for promoters.

The board found that the majority of witnesses, including officers, did not recognize Torbit as an officer and recommends that plainclothes officers taking enforcement action be required to announce themselves as officers and wear garments that identify them as officers.

The board found that Torbit’s safety was compromised when he took enforcement action without backup and that contributed to the situation where he found his life threatened and used lethal force.

The department is already working on some of the recommendations, Police Commissioner Frederick Bealefeld said. Immediately after the incident, plainclothes officers were ordered to wear uniforms whenever they’re on duty, he said. The department has also begun working with a consultant to develop a training program focused on the response to disorder.

“These changes are a good start, but we have much, much more work to do,” Bealefeld said. The goal is to act on all of the recommendations within 90 days, but others, such as a permitting system for club promoters, will require action from other agencies.