SAN DIEGO - The smuggler in the public service announcement sat handcuffed in prison garb, full of bravado and shrugging off the danger of bringing illegal immigrants across the border.
"Sometimes they die in the desert, or the cars crash, or they drown," he said. "But it's not my fault."
The smuggler in the commercial, produced by the Mexican government several years ago, was played by an American named Raul Villarreal, who at the time was a U.S. Border Patrol agent and a spokesman for the agency here.
Now, federal investigators are asking: Was he really acting?
Villarreal and a brother, Fidel, also a former Border Patrol agent, are suspected of helping to smuggle an untold number of illegal immigrants from Mexico and Brazil across the border. The brothers quit the Border Patrol two years ago and are believed to have fled to Mexico.
The Villarreal investigation is among scores of corruption cases in recent years that have alarmed officials in the Homeland Security Department just as it is hiring thousands of border agents to stem the flow of illegal immigration.
The pattern has become familiar: Customs officers wave in vehicles filled with illegal immigrants, drugs or other contraband. A Border Patrol agent acts as a scout for smugglers. Trusted officers fall prey to temptation and begin taking bribes.
Increased corruption is linked, in part, to tougher enforcement, driving smugglers to recruit federal employees as accomplices. It has grown so worrisome that job applicants will soon be subject to lie detector tests to ensure that they are not already working for smuggling organizations. In addition, homeland security officials have reconstituted an internal affairs unit at Customs and Border Protection, one of the largest federal law enforcement agencies, overseeing both border agents and customs officers.
When the Homeland Security Department was created in 2003, the internal affairs unit was dissolved and its functions spread among other agencies. Since the unit was reborn last year, it has grown from five investigators to a projected 200 by the end of the year.
Altogether, there are about 200 open cases pending against law enforcement employees who work the border. In the latest arrests, four employees in Arizona, Texas and California were charged this month with helping to smuggle illegal immigrants into the country.
While the corruption investigations involve a small fraction of the overall security work force on the border, the numbers are growing. In the 2007 fiscal year, the Homeland Security Department's main anti-corruption arm, the inspector general's office, had 79 investigations under way in the four states bordering Mexico, compared with 31 in 2003. Officials at other federal law enforcement agencies investigating border corruption also said their caseloads had risen.
The federal government says it carefully screens applicants, but some internal affairs investigators say they have been unable to keep up with the increased workload.
"It's going to get worse before it gets better," said James Wong, an internal affairs agent with Customs and Border Protection. "It's very difficult for us to get out and vet each and every one of the applicants as well as we should."
The Border Patrol alone is expected to grow to more than 20,000 agents by the end of 2009, more than double from 2001, when the agency began to expand in response to concerns about national security. There has also been a large increase in the number of customs officers.
James Tomsheck, the assistant commissioner for internal affairs at Customs and Border Protection, said the agency was "deeply concerned" that smugglers were sending operatives to take jobs with the Border Patrol and at ports.
Tomsheck said the agency intended to administer random lie-detector tests to 10 percent of new hires this year, with the goal of eventually testing all applicants. His office has contracts with 155 retired criminal investigators, adding 36 since last fall, to conduct background checks.
Comparing corruption among police agencies is difficult because of the varying standards and procedures for handling internal investigations, said Lawrence W. Sherman, the director of the Jerry Lee Center of Criminology at the University of Pennsylvania and an authority on corruption.
But he described policing the border as "potentially one of the most corruptible tasks in law enforcement" because of the solitary nature of much of the work and the desperation of people seeking to cross.