That probe was closed in 2006 without a formal agreement or further review.

On Tuesday, Roy L. Austin Jr., deputy assistant attorney general for civil rights, said such a lack of continuing oversight won’t happen again.

“We’re disappointed to find that the problem is back,” Austin said. “Whatever reforms are put in place have to put in place regardless of who is in charge of the city’s police department. Now there will be a court-enforcement action that the Justice Department will monitor.”

Justice’s findings noted that the police department did not provide close supervision or hold officers accountable for their actions by failing to complete thorough, objective and timely investigations of officer-involved shootings. For a significant number of the shootings, including one that occurred in 2008, the department has not reached a conclusion internally as to whether the firearm discharge was lawful and within policy.

Federal authorities found that the department’s failure to quickly and thoroughly investigate officer-involved shootings undermined accountability, noting that several investigations remained open for more than three years.

They also noted that seven Miami officers were involved in one-third of the shootings, even as the department’s investigations into them continued to be “egregiously delayed.’’

The Justice Department’s investigation involved an in-depth review of thousands of documents, including written policies and procedures, training materials, internal reports, photographs, video and audio recordings, and investigative files.

Miami Mayor Tomas Regalado called the letter from the Justice Department “too harsh.”

”It talks about the past as if it were the present,” he said. “We’ve put a lot of changes in place.’’

Among them: Police Chief Manuel Orosa’s dismantling of the plainclothes tactical teams whose members were responsible for many of the shootings. Orosa also modified the department’s procedures for investigating police-involved shootings. A special team of homicide investigators, instead of Internal Affairs, now handles those cases.

Still, Regalado said court oversight would be good for the city. “A court mandate will guarantee that protocols are in place for the future,” he said.

Orosa, who Justice Department officials credited with instituting some reforms, said in a statement that he welcomed “this long-awaited response” and looks forward to negotiating an agreement with federal authorities.

Orosa pointed out that most of the shootings had taken place under former Chief Exposito, and added that he was thankful to the Justice Department for acknowledging “a significant decrease in police-involved shootings in 2012.” There were four.

In January, the police chief fired officer Reynaldo Goyos, who fatally shot a 28-year-old unarmed man, Travis McNeil, in 2011. The police department’s Firearms Review Board later found he had used “unjustified deadly force.”

His mother Sheila told CBS4 the DOJ report comes “too little, too late” for her son.

“We need to weed out those officers who don’t follow policy and procedures and take it on themselves to be judge, jury, and executioner,” she said.

Exposito, long defiant about the legacy of his tenure as top cop, criticized the findings. He pointed out that during two of the years covered in the report, the department was run by former Chief John Timoney.