 The gangs fought each other in northern Mexican cities, resulting in the deaths of hundreds of people, including some civilians, police and journalists.In 2004 and 2005, Arturo Beltrán Leyva led powerful groups of assassins to fight for trade routes in northeastern Mexico for the Sinaloa Cartel.Through the use of corruption or intimidation, the Beltrán Leyva Cartel was able to infiltrate Mexico's political, judicial and police institutions to feed classified information about anti-drug operations, and even infiltrated the Interpol office in Mexico.