NEW ORLEANS — Two days had passed before the family of Brenting Dolliole learned that he was dead. When his battered body was found by the police, on the Saturday after Thanksgiving, he was simply John Doe.

But he was not just any John Doe.

Mr. Dolliole, who was 22, was the 175th homicide victim in New Orleans this year, a tally that matched the previous year’s homicide count, but with more than a month before 2011 was out. Since Mr. Dolliole’s killing, there have been eight more victims, including two men shot dead in a pickup truck, two shot dead in a sedan and another shot on the street in broad daylight.

Of all the challenges facing the city of New Orleans, none is as urgent or as relentlessly grim as the city’s homicide rate. It was measured at 10 times the national average in 2010, long before shootings on Halloween night in the crowded French Quarter revealed to a larger public what was going on in poor neighborhoods around the city every week. There were 51 homicides per 100,000 residents here last year, compared with less than 7 per 100,000 in New York or 23 in similar-size Oakland, Calif.

“From September of last year to February of this year,” said Mayor Mitch Landrieu in a recent speech, after reciting a litany of killings from one city high school, “a student attending John McDonogh was more likely to be killed than a soldier in Afghanistan.”