Drug war threatens Mexico's richest city MONTERREY, Mexico, April 3 (UPI) -- Growing drug-related violence threatens to take over the city Monterrey, a technology center that is currently Mexico's richest city, researchers said. More than 400 people have been reported killed in Nuevo Leon state so far in 2012, up from 314 in the first three months of 2011, the Los Angeles Times reported Monday. There are visible signs of violence in the city from the bullet holes at the Cafe Iguana, where four people were shot dead in May, to the charred remains of the Casino Royale, where an arson fire killed 52 in August. Jose Juan Cervantes, a researcher at Nuevo Leon state university, said the violence is clearly driving people away, although there are no hard numbers. He said he and his colleagues are wary of visiting towns around Monterrey because of the violence, with some of them believed to be almost abandoned. "We know people are leaving to the (United States) or other parts of Mexico that are calmer, and not just businesspeople, people of the middle class," he said. Javier Guzman, 25, who moved to Monterrey in 2006 to attend the Monterrey Institute of Technology, has a job with a company based in the United States. He plans to move home to Oaxaca. "My parents didn't want me to go to Mexico City because Mexico City was considered crazy and insecure," he told the Times. And now, it's more insecure here.