Washington ( CNN ) -- Mexican drug cartels have used cash and sexual favors as tools to corrupt U.S. border and customs agents , an inspector general investigation has found . In exchange , agents allow contraband or unauthorized immigrants through inspection lanes , protect or escort traffickers or leak sensitive information , said Charles Edwards , acting inspector general of the Department of Homeland Security . Testifying before a Senate subcommittee , Edwards cited the Zetas drug cartel as one of the leaders `` involved increasingly in systematic corruption . '' He did not elaborate on how non-cash methods of corruption , like sexual favors , have been used to corrupt agents . Since October 2004 , 127 Customs and Border Protection employees have been arrested or indicted for acts of corruption , said agency Commissioner Alan Bersin , speaking at the same hearing of the Senate Subcommittee on Disaster Recovery and Intergovernmental Affairs . Mexican President Felipe Calderon 's offensive against the drug cartels , combined with a surge in the hiring of border agents in recent years , have multiplied the risks of corruption , Bersin said . Today , the Border Patrol counts more than 20,700 agents , more than double its size in 2004 . Bersin implied that the rapid hiring spree may have come at the cost of hiring less qualified agents . `` The accelerated hiring pace under which we operated between 2006 and 2008 -- and , frankly , mistakes from which we are learning -- exposed critical organizational and individual vulnerabilities within CBP , '' he said . To face this challenge , the commissioner touted the passage of the Anti-Border Corruption Act of 2010 , which requires that by 2013 , all the agency 's law enforcement applicants must receive a polygraph test before being hired . It also calls for periodic reinvestigations into the background of its agents . `` I can not overemphasize that the overwhelming majority of CBP officers and agents demonstrate the highest levels of integrity every day , '' Bersin said . Edwards noted that the department inspector general 's Office of Investigations has added 10 positions to address corruption complaints among Customs and Border Protection agents . He added , however , that that represented a 6 % increase in the size of his staff , compared with a 34 % increase in the size of the agency as a whole . Since 2004 , his office has seen a 38 % increase in the number of complaints against Customs and Border Protection employees , he said . The inspector general 's office initiated a record 870 investigations in fiscal year 2010 , he said . `` However , '' he added , `` our investigations are complicated by the brutality the cartels use to control their organizations and coerce witnesses , and the sophistication and advanced technologies available to organizations with unlimited money . ''
127 U.S. border or customs employees have been fired since 2010 , an official says . Drug cartels use many people to bribe agents , an inspector general 's report finds . The Anti - Border Corruption Act will pass , an official says .