MEXICO CITY — Six years ago Mexico’s president disbanded the country’s Federal Police and handed security responsibilities fully to the military. Now, his successor has quietly begun to build an elite civilian investigative and special operations force to fight the drug cartels. President Claudia Sheinbaum had already shown a willingness early in her presidency to move away from former President Andrés Manuel López Obrador’s oft-criticized “hugs, not bullets” strategy . It focused on addressing