Whatever nine New Orleans police officers did right or wrong when they unleashed a hail of bullets on Adolph Grimes III six years ago on New Year’s morning, the steps police took in the days that followed can be read as a case study in how to frustrate — or perhaps torpedo — a proper investigation, according to experts on police shootings and to critical reports on how the NOPD has handled them.

Even a 2-year-old federal consent decree that devotes 20 pages to changing how the NOPD deals with the use of force by its officers has yet to end systemic problems with those investigations, according to a report filed last week by a court-appointed monitoring team.

In a scathing 2011 assessment of the department, the U.S. Department of Justice labeled its mishandling of officer-involved shooting investigations “so blatant and egregious that it appeared intentional in some respects.”

Raising questions in the Grimes case were the actions of the cops who together fired at least 70 rounds at the 22-year-old Brother Martin High School graduate or who witnessed the shooting, and those of Sgt. Daniel McMullen Jr., a homicide detective assigned to investigate the incident who ultimately found their actions “reasonable and justifiable.”

The day after the shooting, the nine officers got together in the parking garage at NOPD headquarters, before giving their formal statements, after McMullen determined it “of great importance to have the entire scene re-created to the best of the officers’ knowledge in regards to each of their individual actions during the incident.”

In the presence of an attorney for the Police Association of New Orleans, the group set up police cars on the fourth floor of the garage and went over the incident from 34 hours earlier, step by step.

Then, during individual interviews days later, several officers were told they were being “compelled to cooperate and answer questions in this criminal investigation,” according to transcripts.

McMullen’s investigative report suggests that then-Superintendent Warren Riley ordered the compelled statements, but it is vague on that point. Riley said in a brief telephone interview that the investigation would have followed the usual department protocol, adding that he recalled no specific details about the case.

Thwarting prosecutions

According to experts, the garage re-enactment could easily have poisoned the well, making it far more difficult to flush out what really happened on Gov. Nicholls Street at 3:11 a.m. on Jan. 1, 2009.

Forcing officers to give statements without reading them their Miranda rights, meanwhile, might have thwarted any future prosecution of the officers by making those statements inadmissible as evidence. Worse, any leads in a case that stemmed from such statements could well be seen as “fruit from the poisonous tree,” and thus inadmissible as well.

Police officers — just like other potential defendants — can’t be compelled to cooperate in criminal cases, under the Fifth Amendment.

Under NOPD rules, officers can be made to cooperate in administrative probes used to mete out discipline for departmental violations, but those inquiries are supposed to be kept separate from criminal ones.

The questionable actions in the Grimes case, though clearly out of step with sound policing principles, apparently were not unusual. They may well have followed standard NOPD practice at the time, according to the 2011 DOJ investigation.

The DOJ’s report said the practice of compelling officer statements in criminal probes was “egregious” but apparently commonplace.

The practice of “deeming the statements officers provided to homicide investigators to be ‘compelled,’ ” the report found, “effectively immunized the use of these statements in any subsequent criminal proceeding.

“It is difficult to view this practice as anything other than a deliberate attempt to make it more difficult to criminally prosecute any officer in these cases, regardless of the circumstances.”

U.S. Attorney Kenneth Polite Jr. has declined to discuss the case or why the office dropped its investigation of it last year.

While police policy requires officers to warn or advise a suspect before resorting to reasonable force, failing to do so rarely results in criminal prosecution unless the force itself is found to be excessive, compared to the immediate threat.

Avoiding collusion

In general, officers being investigated in a case that could result in criminal charges — such as a homicide, even one that appears to be justified — should be treated like other would-be defendants, according to Sam Walker, a professor at the University of Nebraska who specializes in police accountability.

That means it’s a no-no to assemble the officers involved in a shooting to arrive at a common narrative before taking individual statements, Walker said.

Notoriously, a group of New Orleans officers allegedly got together at the ruined 7th District police headquarters to hash out an agreed-upon — and allegedly false — version of what happened when cops shot several people on the Danziger Bridge days after Hurricane Katrina.

Unlike that meeting, the one convened by McMullen at the NOPD garage was duly described in his written investigation on the Grimes shooting.

David Klinger, an associate criminology professor at the University of Missouri-St. Louis and an expert on police shootings, said the practice of officers round-tabling a shooting before giving statements has been widely discredited — since around the time Klinger shot and killed a suspect as a young Los Angeles cop in 1981.

“This is something that’s been frowned upon for a little more than three decades,” said Klinger, author of “Into the Kill Zone: A Cop’s Eye View of Deadly Force.”

“It used to be the cops would get together, tell their stories to the investigator and the investigator would piece together a narrative, and nobody seemed to have a problem with that.

“The logic was, you get a clean narrative. The problem with that is, people have different recollections. Even if there is no nefarious intent to come up with a story, what happens is you get improper information because memories are polluted by people talking about it.”

The modern practice is to quickly separate officers involved in a shooting, at the very least to avoid the appearance of collusion, Klinger said.

“We know when we have two officers, we’re going to get at least two stories. Four, we’re going to have four. You have to take the statements and work back and forth between the statements and the physical evidence in order to develop a narrative. There has to be a narrative. It’s just a question of when it comes into play: after you have it all collected.”

No accountability

The missteps after the Grimes shooting are the kind that the sweeping NOPD reforms endorsed by a federal judge in January 2013 clearly were intended to fix.

Over 26 scorching pages, the 2011 Justice Department report — the primary road map for the consent decree — paints a grim picture of a police force barely interested in having officers or their supervisors log reports on their use of force, much less in actually investigating them.

“We found repeated instances where officers used force, including deadly force, in a manner that plainly contradicted NOPD policy or the Constitution, and that endangered the lives of civilian bystanders and other police officers, yet no one in the chain-of-command held officers accountable,” the DOJ report said.

“The prevalence and nature of the force-related misconduct we observed indicates that NOPD officers’ use of unreasonable force in violation of the Constitution is widespread.”

The report said the NOPD had found no violations of its policies on officer-involved shootings in at least six years — dating back to well before the Grimes shooting — and had no “legitimate system in place for investigating uses of deadly force by its officers.”

New policies, procedures and training on use of force in the NOPD make up the first major section of the sprawling reform agreement that Mayor Mitch Landrieu and U.S. Attorney General Eric Holder signed in July 2012. One-sixth of the consent decree’s 492 paragraphs detail what’s required of the NOPD regarding use of force.

Among the new requirements, probes into police shootings as well as other uses of force “indicating apparent criminal conduct by an officer” must now be conducted by a special “force investigation team.” The District Attorney’s Office, the independent police monitor, the FBI and the U.S. Attorney’s Office all must be in the loop.

Homicide detectives can no longer investigate any serious use of force by an officer, and the consent decree requires that “officers involved in a use-of-force incident shall be separated until interviewed.” Group interviews are explicitly barred.

If the case “may proceed criminally, or where NOPD requests a criminal prosecution, any compelled interview of the subject officers shall be delayed,” the consent decree states.

‘A troubling failure’

“Now more than ever before, there is significant oversight and there are more levels of accountability in place regarding these types of investigations,” NOPD spokesman Tyler Gamble said in a statement.

Yet many of the slated fixes remain incomplete, according to the latest quarterly report by the court-appointed team tracking progress on the NOPD consent decree.

The team found “a troubling failure to follow current NOPD policy” in responding to officers’ use of force.

Among the continuing problems, the report said, is “the failure of supervisors to respond to the scene of the use of force to conduct the required investigation, photograph injuries, and obtain force statements for all officers observed using force.”

The monitoring team found required “force statements” missing in a third of the 50 incidents it analyzed, with 40 of the 50 cases lacking evidence that photos were taken to document any injuries.

In more than a third of the 25 high-level uses of force that occurred after the NOPD fully deployed officer body cameras in June, there was no video available to review. In several other cases, the monitor found no indication a supervisor ever looked at the video before deciding whether the force was reasonable.

Data show that if a police officer’s encounter with a subject is recorded on video, “whether through recordings by officers on the scene or by citizens, less force is used,” the report said.

Staff writer Gordon Russell contributed to this report.