SAN DIEGO — Two workers for a Border Patrol contractor were arrested for allegedly conspiring to release illegal immigrants for $2,500 apiece instead of returning them to Mexico.

Christopher Saint Lucero and Manley Lamont Smith work for Wackenhut Corp., which is contracted to escort illegal immigrants to Mexico after they are captured by Border Patrol agents in California, Arizona, New Mexico and Texas .

It was unclear how long the alleged scheme lasted and how many illegal immigrants were released on U.S. soil. According to court documents, Saint Lucero told a colleague that he had been involved in about 10 smuggling attempts.

The men were arrested Sunday after Saint Lucero allegedly escorted a group of illegal immigrants from the Border Patrol's Chula Vista station in suburban. San Diego to the border in Tijuana, Mexico. According to a statement of probable cause, Mexican authorities refused to admit two who identified themselves as Salvadorans. One was an undercover agent.

Authorities say Saint Lucero then brokered the deal to get the two men to Los Angeles. Smith allegedly met them at the Border Patrol station in a company vehicle and offered to hide them.

Saint Lucero and Smith were expected to make an initial court appearances Wednesday, said Debra Hartman, a spokeswoman for the U.S. attorney's office in San Diego. The charge against them, conspiracy to transport illegal immigrants, is a felony.

Hartman did not have contact information for their attorneys, and neither man had a San Diego telephone listing. Wackenhut has suspended both men.

Marc Shapiro, a Wackenhut senior vice president, said the smuggling arrests are the first since the contract began in 2006.

Wackenhut has escorted illegal immigrants back to Mexico more than 1 million times. "This has to be put in context of those numbers," Shapiro said.

Wackenhut is a subsidiary of British-based security giant G4S PLC. According to its Web site, the Border Patrol contract is for $250 million over five years.

Wackenhut, based in Palm Beach Gardens, Fla., is cooperating with investigators, Shapiro said. Hiring background checks turned up no criminal history for either employee.

A Border Patrol spokesman, Richard Smith, declined to comment.

The arrests are the latest in a string of corruption cases that have unsettled the Border Patrol and Customs and Border Protection, which oversees border crossings. A border inspector in San Diego was charged last month with allowing motorists to pass through his booth with illegal immigrants and marijuana in their vehicles.