Torres’s security detail is unique not just in the prominence of its beat — a major American city’s most-visited neighborhood — but also in the fact that it was conceptualized and financed by a single individual, with government support. Staffed by off-duty N.O.P.D. officers in vehicles that bear the N.O.P.D.’s star-and-crescent logo, the force became part of a larger initiative for public-private policing that Mitch Landrieu, the city’s mayor since 2010, had been working to put in place since the shooting on Bourbon Street last summer. In addition to Torres’s force, set to run for a two-month pilot, Landrieu brought in as many as 60 new State Police troopers in the city, paying their salaries through the end of the year with a $2.5 million grant from the New Orleans Convention and Visitors Bureau. While critics argue that such plans undermine traditional police departments and heighten the fragile socioeconomic and racial tensions that already plague urban policing, Landrieu, a progressive Democrat, presented it as part of New Orleans’s newfound embrace of entrepreneurial innovation. ‘‘We all have skin in the game,’’ the mayor said at a news conference announcing the plan, ‘‘so I’m confident this will be successful.’’

Nevertheless, Landrieu’s path to working with Torres was contentious, to say the least. Back in January, following the robbery of his home and the neighboring bar, Torres produced a television ad squarely blaming the mayor for the recent crime wave. ‘‘The French Quarter is under siege by criminals,’’ it began, with Torres himself, who spent $100,000 to air the ad prominently statewide over the next month, providing the voice-over narration. ‘‘We should hold the administration accountable for the failures of not protecting the French Quarter.’’ It was a message that resonated with the neighborhood’s 4,000 residents, a predominantly white and wealthy subset of a city with a majority black population. The week his ads began airing, a hundred or so people gathered for an anti-crime rally in Jackson Square, the city’s historic center, where some waved placards printed with the words WELCOME TO LANDRIEUVILLE! HOME OF ROBBERS, STABBERS & RAPISTS! Dozens of homeowners in the neighborhood had taken to hanging signs from their wrought-iron balconies reading CAUTION. WALK IN LARGE GROUPS. WE ♥ NOPD. WE JUST NEED MORE. Because Torres had the means to express these collective frustrations on air, he quickly became something of a neighborhood folk hero, albeit one with a Gulfstream jet. ‘‘He was giving voice to what everyone had been saying for months,’’ said Meg Lousteau, the executive director of Vieux Carré Property Owners, Residents and Associates, a preservationist group. ‘‘The whole groundswell wasn’t about just one neighborhood, but an expression that something in the city was deeply, deeply wrong.’’

Crime has dropped to record lows in most major American cities, but New Orleans, where wealthy neighborhoods sit side by side with some of the nation’s poorest, continues to struggle. The persistence of crime today stands as the most dominant threat to the resurgent image the city has had since Katrina. Though the murder rate has been in decline, it is still second in the nation, just below Detroit. Nonfatal shootings rose 23 percent last year, leading criminologists to argue that any decline in murders had more to do with advances in emergency medicine, not law enforcement. And with 107 homicides recorded so far this year, the current rate is on pace to increase for the first time in three years, potentially by as much as 20 percent. Meanwhile, over the past few years, other types of violent crime — assault, rape, armed robbery — have risen, some by more than 30 percent, giving credence to Torres’s image of a French Quarter ‘‘under siege.’’ As Peter Scharf, a professor of criminology at the Louisiana State University School of Public Health, explained: ‘‘What happened is that the residents of the Quarter, who have always had great unease with their more impoverished and sometimes violent neighbors, have realized that there is no Green Zone that will protect them from the reality of the city. Whether he meant to or not, Sidney brought up some issues that a lot of people are uncomfortable thinking about. Is the French Quarter a present-day Brooklyn Heights, or is it Bedford-Stuyvesant in the ’70s?’’

Responding to Torres’s attack ads, Landrieu presented Torres with something of a schoolyard dare — one that would ultimately lead the mayor to grant a private citizen extraordinary influence over matters of public safety. ‘‘He made millions and millions and millions of dollars off garbage contracts in the French Quarter,’’ Landrieu remarked on a local news channel. ‘‘Maybe he should just take some of that money and do it himself, if he thinks it’s so easy.’’

Three months later, on an evening in early April, Torres, dressed in skinny jeans and a flowing linen shirt, sat grinning at an outdoor table of an Italian restaurant in the Quarter. ‘‘When the mayor said that thing about me putting my money were my mouth is, I didn’t plan on any of this,’’ he recalled. His decision to take Landrieu up on his challenge was, in Torres’s view, similar to the circumstances under which he founded his sanitation company. In 2005, after Katrina hit, Torres was housing emergency medical workers in the hotels he owned at the time; trash collection had yet to resume, so he rented a truck to haul his garbage to the dump. ‘‘Other businesses asked me to pick theirs up, and so I slapped my name on the truck. One of my first contracts was the Quarter, and within a few years we were picking up over 14,000 homes in the city and state.’’

As he spoke, one of the N.O.P.D. officers in his employ — making $50 an hour, a premium rate for off-duty details — drove past in a Polaris. The force had been on the streets for two weeks, and while small in numbers, the sudden ubiquity of their flashing blue lights, combined with the privately funded presence of the State Police, provided something the Quarter had been lacking: the sense that the police were always nearby. ‘‘What I’m doing now isn’t all that different from the trash thing,’’ Torres said. ‘‘It’s about seeing a need — an unfortunate need — and stepping up to fill it.’’