As 2012 wound down Monday, police in New Orleans had investigated 193 murders for the year, six fewer than they had in 2011. That slight, 3 percent decrease was fueled in part by a period of 18 days without a single murder, from Oct. 24 to Nov. 10.

It was the longest such stretch in recent memory in the city, which will almost certainly retain its title as America's murder capital.

Coincidence or not, the respite in murders came right when Mayor Mitch Landrieu, Police Superintendent Ronal Serpas, District Attorney Leon Cannizzaro and former U.S. Attorney Jim Letten met with 40 probationers and other convicts behind the closed doors of a state courtroom. The authorities promised, among other things, to deploy every state and federal law enforcement resource available against their gangs or associates the next time gunfire could be linked to anyone in the room.

That so-called "call-in" was an early phase of "NOLA for Life," billed by Landrieu's administration as a comprehensive strategy to reduce killings in New Orleans. It is not known whether the murder-free period in New Orleans merely coincided with the "call-in" or was a tangible result from it, but city leaders hope there will be many more similar stretches as "NOLA for Life" evolves.

Spike Lee and Mitch Landrieu's NOLA for Life Campaign Director Spike Lee speaks with New Orleans Mayor Mitch Landrieu at the Joy Theater during the launch of the new "Flip the Script" PSA campaign by Spike Lee's advertising company that is part of the mayor's "NOLA For Life" anti-violence campaign in New Orleans, La., Tuesday, Oct. 2, 2012. (Photo by Matthew Hinton, NOLA.com / The Times-Picayune)

"It remains my top priority as Mayor of New Orleans to end the cycle of violence on our streets," Landrieu wrote in a letter to residents introducing the plan. "Ending murders in New Orleans will not be easy, but it is a fight we must all be in together."

Landrieu says that the murder epidemic in New Orleans is largely confined to African-American men between the ages of 16 and 30, both victims and perpetrators. Murder is the leading cause of death for that demographic group, he said.

Ramon Antonio Vargas and Naomi Martin

NOLA.com | The Times-Picayune

A central part of his strategy is to emphasize that all young people are worthy of love. "We have created a culture where murder is seen as rational," the mayor said. "It's upside down. We want to focus on the idea that African-American kids are valuable. It's an affirmation of love."

Between 2008 and 2010, New Orleans saw about 175 murders or so annually. That changed in 2011, when New Orleans registered 199 murders, the most since the 210 murders recorded in 2007.

Landrieu notes that the upswing in murders really goes back decades, with New Orleans averaging 242 murders a year since 1979. Murders peaked in 1994, when the city recorded 425.

This year, there were 204 homicides in all, the New Orleans coroner's office says. But 11 of those were not classified as murders by police. Killings that, for example, happened unintentionally or were committed justifiably (such as in self-defense) are not considered murders.

Among 2012's murder victims were Harry "Mike" Ainsworth, 44, who was killed in front of his two sons in Algiers Point as he tried to stop a carjacking; Briana Allen, 5, one of two people fatally shot at a birthday celebration in Central City; Kendall Adams, 3, and Kelsey Adams, 4, who were allegedly murdered by their mother; Valan May, 24, a UNO sophomore who investigators think was killed by teenagers belonging to a street gang; Marguerite Washington, 18, a Dillard University freshman struck by bullets police say were shot at her boyfriend, who was wounded; and Bruce Cucchiara, 57, a Covington businessman killed and robbed while scoping out a local investment property. Those cases received significant attention from the news media, and arrests have been made in all of them except Cucchiara's.

Serpas on Monday lauded NOPD for the small decrease in murders, especially because the department ended the year with 112 fewer officers than it had started with. "To look at you and say we have reduced crime with fewer police officers gives me great hope for 2013," remarked Serpas, who added that his agency employed "the best technology" available to more efficiently assign its limited manpower and resources.

Serpas expects things to be better staffing-wise in 2013. The City Council has appropriated money for two new recruit classes, which should ensure the NOPD will maintain a level of 1,260 officers.

Serpas thanked the City Council for putting "a stop to the bleeding of police officers." He added, "This will be the first year I've been superintendent we'll see the sliding (of manpower) stop."

Serpas on Monday also repeated points he often mentions in discussions about murder in New Orleans: half of identified murder suspects and a third of murder victims have prior weapons-related arrests. Many murder victims in New Orleans are killed by intimates, associates, relatives or acquaintances, making the violence difficult to police.

Nonetheless, officials acknowledge that New Orleans' murder rate is unacceptable. New Orleans' murder rate is approximately 10 times greater than the national average and much higher than in other comparable cities.

With a population of 360,000 people, the city's murder rate in 2012 was more than 53 murders per 100,000 people. By comparison, the much-larger city of Chicago registered at least 500 murders this year, making its murder rate about 18 per 100,000 residents and causing alarm there.

Beyond the call-in, as part of "NOLA for Life," authorities have formed a task force of local and federal law enforcement agents dedicated to disrupting violent gangs and groups, made up of a relatively small number of people causing a disproportionate share of shootings in communities.

Those directed to the "call-in" included members of those gangs. Landrieu has said authorities have identified about 600 gang members in 39 groups locally. The Group Violence Reduction Strategy that officials want to use to disrupt those gangs with was devised by criminologist David Kennedy, and it has succeeded in Chicago, New York, Philadelphia and Boston.

Separately, the city has started up a local version of the program "CeaseFire," pioneered in Chicago, which sends out violence "interrupters" in the wake of homicides. The interrupters, typically ex-cons, try and calm people they suspect might try to commit retaliatory killings. The city's pilot program is focused on a 10-block stretch of Central City.

Alongside those efforts, the murder-reduction plan will focus on building up the capacities of social service and support providers in communities most plagued by violence. Other aspects of NOLA for Life aim to seek and sustain employment for at least 125 ex-offenders, both adults and youths; reduce blight; and provide mental health support for victims of violence.

Some in town aren't convinced "NOLA for Life" will lead to meaningful change on the city's streets. Tamara Jackson, the executive director of anti-violence campaign Silence Is Violence, questions whether support for "NOLA for Life" will vanish in the event of a change in mayoral administration.

She also wonders whether the members of the anti-gang unit are adequately trained or equipped to help make a substantial dent in New Orleans' staggering murder rate.

"What happens when we get another mayor, and we get all kinds of new initiatives?" Jackson, who lost her father to gunfire, said. "What happens to these people when the promises have been made? ... They have come up with great ideas, but we're still in a situation where we are losing our young people every day to senseless acts of violence."

Landrieu, though, contends that "NOLA for Life" will indeed succeed because the strategy counts not only on the government but also on contributions from partners in the community. "We can and we must prevent murders," the mayor writes. "Our city has overcome hard challenges before and I believe the people of New Orleans, with the help of our partners, have the power to create safe and healthy neighborhoods where generations to come will flourish."

Note: NOLA.com | The Times-Picayune Managing Producer Gordon Russell contributed to this report. NOLA.com | The Times-Picayune's 2012 murder count was slightly behind NOPD's, so the decision was made to go with NOPD's count for this story.