SAN ANTONIO -- Investigators with the Department of Public Safety said they've broken up an illegal operation that could have put some untrained big rig drivers on the road.

One of the people arrested in the undercover sting is a DPS employee.

Henrietta Parra, 50, who worked as a driver's license technician at the DPS office on South New Braunfels Road, is charged with bribery and tampering with government documents.

Also in jail is Esgar Lopez, 44, accused of brokering the illegal deals at his south side business, Lopez and Sons Auto Shop.

He faces two counts of bribery.

According to an affidavit, Lopez collected money from an undercover DPS agent, posing as a trucker, as well as at least one real driver.

It says he then promised both men he'd introduce them to someone who could help them get their commercial drivers licenses, guaranteed.

The affidavit shows Lopez brought the agent and the driver to the South New Braunfels location where they took written tests for their licenses under the supervision of Parra.

During the tests, it says, Parra supplied both men with the correct answers.

Later, she also signed off on paperwork showing they'd passed their road tests which, in reality, they had not even taken, the affidavit says.

Investigators believe the illegal activity took place between April and October of last year.

However, they say they're still looking into whether the operation may have been more widespread.