New Orleans police were investigating the city's sixth murder in 24 hours Saturday night.

Responding to a call, police found a 31-year-old man lying in the middle of a Central City street with multiple gunshot wounds, officer Garry Flot said. He was pronounced dead at the scene.

The murder followed that of three brothers and a friend killed in a neighborhood not far from the French Quarter, and a fifth person was gunned down in a separate incident hours later.

The shootings were the latest round of killings as the city struggles to rein in drug- and gang-related violence that has shadowed the recovery from Hurricane Katrina.

In mid-June, Gov. Kathleen Blanco sent the Louisiana National Guard and state police to New Orleans to help fight crime there after five teenagers were shot to death in a single attack.

Such sensational murders have a crippling effect on the city's struggle to rebuild its tourism industry and persuade evacuees to return, said New Orleans city councilman James Carter, who heads the council's committee on crime.

"Unfortunately, it's not a new reputation," he said. "People go back to those old days when we had so many murders. We're no where near that, but we have to make sure we don't get back there."

That will take more than strong law enforcement, Carter said.

"The spotlight Katrina put on the city showed the real reason for these murders — abject poverty and a poor education system," he said. "We have to go from looking at this as a strict law enforcement situation and take a more holistic approach."

The latest shooting happened in Central City, where most of the killings have occurred. The others, however, did not happen in the high-crime areas police have been targeting in their drive to stamp out the violence, police Superintendent Warren Riley said Saturday.

Detectives were uncertain about the motive and were still looking for the assailants Saturday.

The three brothers — 16-year-old twins and a 21-year-old — were killed late Friday in the Treme neighborhood, as was their 39-year-old friend, Riley said. All four lived nearby.

They were sitting on the porch of an abandoned house when two men walked by, then turned around and started blasting, Riley said.

The fifth shooting happened early Saturday in the Gentilly neighborhood, an area that was severely flooded and has been slowly rebuilding. Police said they found a man dead in a street after they received reports that shots had been fired.

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So far this year there have been 78 homicides in New Orleans, still far fewer than normal in a city accustomed to violence, but enough to cause residents to fear a return to the days when New Orleans was the murder capital of the nation.

Murder and other crimes had plummeted in the first months after Katrina hit New Orleans on Aug. 29 and flooded 80 percent of the city. The city's population is currently estimated to be about half the pre-storm total of 465,000.

People who "live the life" of drugs and violence were taking their toll on the rest of the residents, Riley acknowledged Saturday.

"It is an unfortunate and very, very sad situation for those good-quality citizens who are living with the guidelines of what we all consider normalcy — the norms of society," Riley said.

Last month, five teens were killed as they sat in or stood near a sport utility vehicle. A 19-year-old man with a lengthy juvenile record was later arrested in the deaths.