SAN DIEGO -- A San Diego County jail guard is scheduled to stand trial, the first in the wake of a highly publicized federal investigation into the Mexican Mafia.

In 2009, the Violent Crimes Task Force apprehended 40 people suspected to have ties to the Mexican Mafia as part of Operation Keys to the City.

While details were kept quiet at first, it turns out one of them arrested was Andres Villota, a San Diego County Sheriff's deputy working at the County Jail downtown.

Andrea Gomez, a confidential informant, was behind the arrests and she recently spoke exclusively to the 10News I-Team about her role in the operation.

Gomez said she wore a body wire as she worked as a facilitator. She passed orders and contraband from Mexican Mafia members on the outside to those behind bars.

"I literally ran all the prisons. Donovan, San Diego Central Jail, I ran it. Vista, George Bailey, Chula Vista," she said.

Villota was only on the job a few years. He was a correctional officer assigned to the Central Jail with access to inmates. It's still unclear just what he did, but he is charged with one felony count of a peace officer filing a false report, two misdemeanor charges of destroying or concealing evidence and one more misdemeanor of unauthorized possession of a hypodermic needle.

The FBI had targets and put Gomez on the hunt.

She said, "When they came and approached me, that is what they really wanted -- the dirty cops, the dirty cops who were taking [expletive] in."

Gomez may or may not take the stand. She is currently awaiting federal prosecution on methamphetamine charges, but the fruit of her labors -- the taped conversations -- will be evidence against Villota.

Villota's defense attorney, Ward Clay, told 10News that Gomez's testimony would be "dubious" and he's confident Villota will be acquitted.

Trial will begin on Oct. 18.