Mexico City mayor under fire over disappearances of 12 MEXICO CITY - Miguel Angel Mancera, the former top prosecutor in Mexico's capital, rode his crime-fighting reputation to the mayor's office, promising voters a superior level of safety as the cornerstone of a revitalized metropolis. But six months into his term, Mancera, is fighting accusations that he has mishandled the highest-profile case of his mayoral career: the disappearances last month of 12 people from a bar in the heart of Mexico City. The case remains unsolved, and the criticism of Mancera, a potential presidential candidate for the left-wing Democratic Revolution Party, or PRD, has been withering. Mancera suffers from "political autism," wrote a columnist on the website Sin Embargo. The mayor has not proved to be "a distinct or distinguished head of government," declared a writer for Proceso newsmagazine. Perhaps even worse for Mancera is that the disappearances, along with other recent acts of violence, have sparked a national debate about whether Mexico City is lapsing into a period of destabilizing drug-gang violence after several years as an oasis of calm compared with other Mexican cities. Many think the answer is no. But then again, nobody knows for sure. "I would like to believe, as an inhabitant of this city, that it is not, but I cannot rule it out," said Juan Francisco Torres Landa, secretary of the civic group Mexico United Against Crime. The capital's reputation as a haven from cartel violence in recent years has made it a magnet for Mexicans whose cities have been beset by shootouts, beheadings and streets blockaded by burning cars. But horrors loom nearby, particularly in the neighboring states of Morelos, the province of the Beltran Leyva cartel, and Mexico, which is dominated by the cartel known as La Familia. Mexico City is by no means perfect. The U.S. State Department says armed robberies, street crime and kidnappings are "daily concerns." The 2011 homicide rate of 8.8 per 100,000 residents in the federal district, which encompasses the capital, was roughly one-tenth the rate for the northern state of Chihuahua. Occasionally, there are outbursts of spectacular public violence of the kind considered a cartel-war hallmark. Last June, federal police said to be protecting a drug smuggling operation killed three fellow officers in the middle of the bustling Mexico City airport. As a mayoral candidate, Mancera took some credit for the plummeting city crime rate during his time as top prosecutor, including a 12.5% reduction from 2010 to 2011, under the administration of Mayor Marcelo Ebrard. Mancera won the election handily and took office in December. But even if Mancera can boast that he helped reduce the high levels of crime that once beset Mexico City, it would be difficult for him to ensure a safe environment if organized crime groups have in fact decided to launch a period of terror. The mayor last week pressured his team to solve the case of the 12 disappearances, telling reporters that "no one is guaranteed a place in my government if they don't get results." On Tuesday, the city prosecutor's office announced that the head of the missing persons bureau, Francisco Carlos Trujillo Fuentes, had stepped down and was being replaced. Numerous theories exist as to why safety improved in this city of 20 million people during Ebrard's tenure. Supporters say the Ebrard team was wise to install thousands of video cameras, hire sharp, innovative police leaders and develop social programs to give kids alternatives to crime. Others suspect that the drug cartel bosses have designated Mexico City as a "safe zone" for their families, which has prevented it from becoming an urban battleground the way cities such as Ciudad Juarez, Monterrey and Guadalajara have in recent years. Jorge Chabat, a professor at the city's Center for Economic Research and Teaching, said cartel bosses may have been operating under the assumption that major crimes would generate much more attention in the media-saturated capital than elsewhere and result in more heat from authorities. A report from the Mexico City Citizen Council shows some homicide and gun-related statistics up slightly in the first five months of this year compared with the same period last year. But auto thefts and home-invasion robberies have declined. Torres said the May 26 disappearances of the 12 young men and women, whose ages ranged from 16 to 34, garnered more media attention than other similar crimes because they occurred in the Zona Rosa, or Pink Zone - a centrally located, formerly trendy neighborhood that has fallen on hard times but is nonetheless well known to the Mexican elite. In tougher, working-class neighborhoods, Torres said, "they'd probably say, 'Why are you guys so concerned about this? This is what happens every day in this city.' The details of the disappearances are murky. Family members said the bar patrons had been stuffed into SUVs by armed, masked men, a hallmark of mass kidnappings in other Mexican cities. But city prosecutor Rodolfo Rios has shared surveillance tapes that show the bar patrons being loaded into a number of compact cars by men who do not appear armed or masked. Rios said authorities could place only eight of the 12 missing people at the bar.