New Orleans — After years of maintaining a chilly and often ineffective partnership, the New Orleans Police Department and Orleans Parish District Attorney’s Office are slowly finding common ground and it’s creating positive results in the criminal justice system, according to a local watchdog group.

The Metropolitan Crime Commission released the second of its two annual reports this week, and it showed that increased cooperation between police and prosecutors has resulted in more high-quality arrests and prosecutions.

Commission President Rafael Goyeneche said his group examined felony arrests and prosecutions from July 2010 through June 2012. It found increases in the number of arrests, along with the highest levels of successful prosecutions since the group began examining those statistics in 2007.

Those figures are signs of growing collaboration between two of the most important agencies in the city’s criminal justice system, which is a positive sign for the city as a whole, Goyeneche said.

“Those two agencies are joined at the hip,” he said. “Historically in New Orleans over the last 24 years they have not enjoyed the best working relationship.”

The crime commission keeps a record of felony arrests and the ultimate results of those cases as a way to hold public agencies accountable for their performance, Goyeneche said.

Before Hurricane Katrina, it had become obvious that the way those agencies measured success and worked together was flawed, he said.

The Police Department focused too heavily on total number of arrests, despite the fact that most of those arrests were for misdemeanor crimes or warrants from other jurisdictions, he said.

The two agencies warred over the fact that police only had to meet the probable cause standard to make an arrest, while prosecutors must prove cases beyond a reasonable doubt to get a conviction. At one point, 85 percent of arrests were for misdemeanors, only 50 percent of arrests proceeded to prosecution and only a small percentage of those cases ended with convictions, he said.

Now, those numbers are trending in a better direction.

“What we’re seeing is that the Police Department and district attorney have recognized that they can’t be successful without the support and cooperation of each other,” Goyeneche said.

Police Superintendent Ronal Serpas said the commission’s report validates his belief that his department is making key improvements. Officers still make arrests based on probable cause, but they don’t just hand those cases over to prosecutors without follow-up, he said. Extended investigations help to strengthen cases and make for more successful prosecutions.

“We have to be willing stay with that case all the way through with the prosecutor,” Serpas said. “I think the report continues to be a good sign, independently conducted, that we’re moving in the right direction.”

He noted that police use more discretion in taking people to jail for misdemeanors and issue more citations. Every time an officer takes a suspect to jail, it can mean hours away from patrols and answering calls for service. However, Serpas said that at times arrests for assumed low-level crimes can result in capturing serious criminals. “A low-level offender in front of you today doesn’t mean he’s living a low-level lifestyle,” Serpas said.

Assistant District Attorney Chris Bowman said improving the relationship between prosecutors and police officers has been a goal of District Attorney Leon Cannizzaro since he took office. The report shows that although some problems persist, progress is being made.

“We’re pleased with the results but by no means is the work done,” Bowman said.