NEW ORLEANS, USA (AP) – In a recent university experiment, police fired 700 blank rounds in a New Orleans neighbourhood in a single afternoon. No one called to report the gunfire.

New Orleans residents are reluctant to come forward as witnesses, fearing retaliation. And experts say that is one of several reasons homicides are on the rise in the Big Easy at a time when other US cities are seeing their murder rates plummet to levels not seen in decades.

The city’s murder rate is still far lower than a decade ago, when New Orleans was the country’s murder capital. But in recent years, the city’s homicide rate has climbed again to nearly 10 times the national average.

“We’re going in the reverse of 46 of the top 50 cities in the United States. Almost everyone is going down, but we’re going up,” said criminologist Peter Scharf. “There is something going on in New Orleans that is not going on elsewhere.”

Many of the killings are related to drugs and gangs – but police say more are simply disputes that get out of hand.

Along with reluctant witnesses, experts say the city has too few police and inexperienced prosecutors. Coming up with more cash has been a chronic problem for money-pinched New Orleans, which typically lurches from budget to budget.

“As far as law enforcement goes, money is at the root of everything,” said Lt David Benelli, head of the police officers’ union. “We need more personnel, more equipment. The DA’s office needs more people and money. The corrections department needs more people and space to house prisoners.”

Homicides hit their historic peak here in 1994, with 421 dead – more per-capita than any other US city that year. Within just five years, the number was slashed by nearly two-thirds, to 159, as homicides plummeted nationally.

But by last year, the number in New Orleans had crept back up to 265. There had been 192 this year by mid-August, compared with 169 at the same time in 2004. Adjusted for the city’s size, those numbers dwarf murder rates in Washington, Detroit, Baltimore, Atlanta, Chicago, Los Angeles and New York City.

For police, recruitment is a continuing problem. The department has a poor image in the community, with allegations of brutality and corruption dating back decades. The city now has 3.14 officers per 1,000 residents – less than half the rate in Washington, DC.

Scharf, director for the Centre for Society, Law and Justice, said extra police are not always the solution to crime.

“My heart goes out to these police officers,” Scharf said. “They’re fighting public apathy, racial division and a dysfunctional court system. They work their hearts out and nothing ever happens to these cases.”

Only one in four people arrested in the city for murder is eventually convicted, according to a recent study by the New Orleans Police Foundation, a private nonprofit group.

According to the study, 42 per cent of serious crime cases reviewed by prosecutors – about 22,000 – were turned away between 2002 and 2004 because the cases were not deemed suitable for court.

District Attorney Eddie Jordan said the lack of eyewitness testimony was one reason for the dropped cases. New Orleans has had such a problem with retaliation against witnesses – including murder – that the district attorney’s office took the unusual step of starting a local witness protection programme.

Witnesses may also be reluctant to talk to police because of the department’s struggles with allegations of brutality and corruption.

In the 1990s, two rogue cops turned out to be killers. Former Police Superintendent Richard Pennington, now Atlanta’s chief, is credited with cleaning up the department, purging scores of bad cops during the 1990s.

But recently, complaints about police brutality have surfaced again.

In March, a New Orleans ritual – the annual St Joseph’s night assembly of the Mardi Gras Indians, black residents who dress up in elaborate costumes – was marred by complaints that officers roughed up members.

Police Superintendent Eddie Compass has tried to burnish the department’s image with community outreach, including ordering officers to address people as “sir” and “ma’am.” But the same day that order came down, the department was dealt another blow when a drug-related gun battle erupted in a residential neighbourhood, leaving four people dead.

Rafael Goyeneche, a former state prosecutor who now heads the private Metropolitan Crime Commission, said both the district attorney and the police are trying to seriously tackle violent crime – but under current budgets, that will be tough.

“Unless they are given additional resources, and that means manpower and more money to recruit and retain, I’m fearful that we are not going to make any lasting and meaningful progress in combatting crime in this community,” Goyeneche said.