Story highlights Jose Luis Zavala is accused of aiding drug smugglers

Investigators say he helped steer smugglers into his lane at international crossings

His apparent failure to spot 3,000 pounds of pot in a van raised questions

A U.S. Customs and Border Protection Officer was behind bars Monday after being arrested for allegedly helping drug traffickers move their product into the United States.

The arrest of Jose Luis Zavala, 38, a CBP officer in Brownsville, Texas, follows an investigation by Homeland Security Investigations and Department of Homeland Security Office of Inspector General, the CBP said.

Zavala has been with the CBP for seven years and is now on administrative leave, the agency said.

According to a criminal complaint, Zavala came to the attention of investigators on November 19, when a van carrying about 3,000 pounds of marijuana tried to enter the United States at the Gateway International Bridge in Brownsville.

The 2004 Ford cargo van pulled up into the lane where Zavala was inspecting vehicles, the complaint states, but the van was only inspected after it was selected for a random screening.

Inside the van were the 3,000 pounds of marijuana, which, the complaint states "was not hidden in a compartment or disguised to appear as legitimate cargo."

The random inspection was a decision Zavala could not control.

When asked about what happened, Zavala told fellow agents that the driver had a valid ID, and that the driver escaped back to Mexico on foot after being told of the random inspection, the criminal complaint states.

Investigators learned that the ID did not belong to the driver, but to another person who agents interviewed on November 22, according to the complaint.

This person, now a confidential source for the government, told investigators that he sold his ID to a drug trafficking organization, and that the group was aided by a U.S. agent, the document states.

The interview led to the identification of Zavala as the U.S. agent that the source knew as "Pepe," according to the document.

The source identified Zavala in a photo, and his description of Zavala's vehicle matched the truck the agent drives, the complaint says.

Among the evidence collected by investigators were some text messages sent to "Pepe" by the source, with what investigators say was code for when and where to cross.

Zavala is facing drug smuggling and corruption charges.

"We do not tolerate corruption or abuse within our ranks, and we fully cooperate with any criminal or administrative investigation of alleged misconduct by any of our personnel, on or off duty," CBP said in a statement.