gangsters in this city seem to fear no one, especially not the police. They steal and kill in broad daylight, and some of their actions are designed to instill terror. One day in late August, two vehicles pulled in front of the Suspiros Pastry Shop along busy Constitution Avenue, one of the city's most heavily traveled roads. An elderly unarmed guard at the shop, driven by curiosity, then fear, watched through a window as armed men got out of the vehicles, leading an apparent hostage who had a steel chain around his neck like a noose. The gangsters led their victim to a pedestrian overpass, pulling him up the stairs by the chain. At the top, the guard related, one gangster took out a large ice pick. "He plunged the ice pick in the man's chest," the guard said, asking that his name not be used for fear that gangsters might come after him, too. As the victim fought for his life, the assailants tied the chain to a bridge railing and tossed the man over, where he dangled, bleeding but still alive, above traffic on a service road. The gangsters hung a banner, then descended to street level, where they fired their AK-47 assault weapons a few times in the air. "Then they fired into the man's hanging body," the witness said. Terrified motorists passing along Constitution Avenue and witnessing the scene kept on driving. Time of attack: 11:50 a.m. on Aug. 23. "This is the third guy they've hung from a bridge in Monterrey," said Tatiana Clouthier, a former mayoral candidate and civic activist. Police arrived too slowly to confront the gunmen or make arrests. The proximity of police to many crime scenes, including the Aug. 25 firebombing of a casino that left 52 people dead, has only reinforced suspicions among Monterrey residents that police are colluding with gangsters. A state police officer is in jail, accused of serving as a lookout for the gangsters who carried out the casino firebombing, and prosecutors say they believe other police were involved. Criminal infiltration of police in Nuevo Leon state is not new. In 2009, the state's top public security official told U.S. diplomats that he believed 50 percent of state and municipal police had been bought off by drug cartels. The U.S. account of the conversation is among the 251,287 diplomatic cables made public by WikiLeaks. The concern about police, Clouthier said, is that "they either are in collusion or they are incompetent. Whichever possibility is tragic."