Orleans Parish District Attorney Leon Cannizzaro has been lauded for his success in melting years of frosty relations between prosecutors and police detectives — a distrust that too often resulted in aborted cases and finger-pointing. 

But tensions have erupted lately between the two agencies over leadership of the New Orleans Police Department's homicide squad, an undermanned unit that has struggled to keep up with the city's spiraling murder rate. 

Last month, the unit's commander, Lt. Jimmie Turner, refused to allow two of his detectives to testify before a special grand jury that handles gang cases and that was considering evidence in a string of recent killings. 

Turner ordered the detectives to ignore the invitation from Cannizzaro's office to appear on March 8 without a subpoena, police sources said. He told his detectives the same policy would apply to any future grand jury appearances.

That was contrary to longstanding practice, and it incensed a DA's Office that wasn't expecting a fight to secure key testimony from police as it sought to indict 19-year-old Errol Krish and three others in connection with four murders earlier this year. 

The reason for Turner's recalcitrance is unclear, but his order drew the ire of First Assistant District Attorney Graymond Martin, who fired off a bitter letter to NOPD Superintendent Michael Harrison.

Martin demanded answers about what he described as a "frustrating" break from "our customary collaboration," according to the letter, which The Advocate obtained through a public records request. Because the detectives did not show up, the grand jury was sent home that day, he wrote.

Martin went on to describe Turner's mandate as "astounding," particularly for a case built by the Multi-Agency Gang Unit, a team that Mayor Mitch Landrieu has credited with helping yank some of the city's most violent gangsters off the street.

He also wrote that the process of securing subpoenas, which require a judge's signature and force officers to show up at a designated hour, was unnecessary and would result in significant "dead time" for homicide detectives.

"With an escalating murder rate, I cannot understand why we are going to go backwards and retarding the process," wrote Martin, who was once a New Orleans cop himself. "Can you explain to me why?"

Asked about the letter Thursday, NOPD spokesman Beau Tidwell said: "Chief Harrison spoke with (Martin) about this matter, and the issue as to requiring subpoenas has been resolved."

He didn't elaborate, and other questions about Turner went unanswered, including whether the department was reviewing his performance or considering discipline against him in the wake of his controversial order.

Martin's letter, however, made clear that Cannizzaro's office has a problem with Turner's leadership of the high-profile homicide unit.

Christopher Bowman, a spokesman for the DA, said Harrison has since assured prosecutors that Turner's dictate has been revoked. 

The same grand jury that Turner told his officers to shun returned last week to issue a 17-count indictment against Krish, Edmond Bacchus, Corey Coleman and Tyrone Scott in connection with the four murders and other attempted killings. Citing grand jury secrecy rules, Bowman declined to say whether the previously barred detectives appeared last week, with or without a subpoena.

Asked if the dust-up has soured relations between the DA's Office and the NOPD, Bowman said his agency doesn't have a problem with Harrison. 

"When we informed him of a problem, he was quick to fix it," Bowman said, adding: "There are some unanswered questions as to how we got there in the first place, and why the commander of homicide did this."

Law enforcement sources say that, at least for now, Harrison is standing by Turner, the man he appointed to the homicide commander's post in July 2015. Turner succeeded Lt. Nicholas Gernon, now the head of the 8th Police District, which patrols the French Quarter and Central Business District. 

Turner was front-and-center Tuesday when police cordoned off blocks of Bourbon and St. Ann streets in the Quarter after a murder suspect barricaded himself in an apartment.

But sources within the NOPD, who spoke on condition of anonymity because they were not authorized to comment, said the order that infuriated the DA vividly illustrates a domineering leadership style that has soured morale within the homicide unit.

The sources said Turner isn't shy about it. On his office wall, he has hung two traffic signs pointing in opposite directions. One says "my way." The other: "highway."

Turner, a 25-year NOPD veteran who has spent most of his career on the homicide squad, leads a unit that is under intense pressure as it grapples with near-daily killings.

NOPD statistics show that the unit’s clearance rate – the number of cases solved by either an arrest or a special circumstance, such as the death of a prime suspect – has dropped over the past two years.

In 2015, the Police Department claimed a 35 percent clearance rate for homicides in statistics submitted to the FBI. The clearance rate slid to 27 percent last year.

The unit’s clearance rate remains low in 2017. Officers had made arrests in 10 of the year’s 54 killings through Wednesday, or about 19 percent. Numerous high-profile killings remain unsolved: a woman and her two young children, a pizza deliveryman, a double homicide outside a high school basketball game in Algiers, two transgender women. 

Two of the 10 cleared homicides were handled by the NOPD's Child Abuse Unit, meaning last week's gang indictment accounted for half of the remaining 2017 homicides that have led to arrests.

New Orleans' clearance rates over the past couple of years are far lower than in Jefferson Parish. In January, Sheriff Newell Normand said that his detectives had solved 84 percent of the 44 homicides that happened in unincorporated Jefferson in 2016.

The NOPD’s clearance numbers are also well below national averages. The FBI says that 61.5 percent of murders in the United States were solved in 2015. 

As the force’s overall manpower declined over the past few years, so did the homicide section’s staffing. It had 30 detectives handling new murders in May 2013, according to an inspector general report.

This year, New Orleans has 18 homicide detectives handling new cases — meaning detectives are already approaching a national recommended average of four to five killing investigations per year.

Turner's tussle with Cannizzaro's office doesn't help matters, police sources said.

They said it feels like a throwback to the infamous dueling press conferences the NOPD and DA held over the dismissal of a murder case in 2007, when the city's criminal justice system was still reeling in the aftermath of Hurricane Katrina. 

Back then, DA Eddie Jordan claimed he jettisoned the case in question because the sole witness disappeared. Almost immediately, Police Superintendent Warren Riley followed with an announcement that his officers had found the witness with just a few hours of effort.

Two police sources say the challenges within the homicide unit may be exacerbated by Turner's icy relationship with his boss, Criminal Investigations Division Commander Doug Eckert.

Eckert and Turner practically don't speak to each other, which is especially awkward given that their offices are next to one another, the sources said.

Yet, in an interview conducted before Martin's letter was released, Eckert didn't hint at any internal divisions, saying the homicide unit was working hard despite the mountainous case load.

He added that it was far too soon to draw conclusions about the clearance rate for 2017, a year that started off with a surge in deadly violence — although he acknowledged the rise in killings has put a “strain” on his homicide detectives.

“We really got pounded from July to February, and it was tough,” he said.

Recent years have brought additional pressures for detectives who must now sift through social media and canvass for surveillance video from private cameras, he said.

“Some of them get frustrated, but they haven’t stopped,” he said. “When the bell’s rung and it’s their turn, they are always willing.”

Eckert said he regularly asks Harrison for more detectives to fill out the homicide section. However, he understands the chief is working under the constraints of depleted manpower.

Eckert acknowledged the loss of several detectives in the past two years, including Marc Amos, a sergeant with over two decades of experience who left for a job at the attorney general’s office. But he said he believes that attrition in homicide is no worse than elsewhere at the Police Department.

When the homicide section dwindled after Hurricane Katrina, the department tried desperate measures like calling in FBI agents for help and loaning district detectives to the section. Eckert said the plan now is to wait on new Training Academy classes to free up veteran officers to become detectives.

“I think relief is going to come sooner than later,” Eckert said.