SAN ANTONIO – It's the FBI's No. 1 criminal priority and it has nothing to do with terrorism, but those who are accused of committing the crime often terrorize their communities and most people don't even realize what's happening.

The crime is public corruption and in South Texas, crooked officials are keeping FBI agents very busy.

"Unfortunately, corruption is a growing business here in southern Texas, so we have had to move agents from some of our other priorities over to work the public corruption cases," said Christopher Combs, FBI special agent in charge, San Antonio. "We've certainly put a laser focus on it here because we believe it is a problem, but it's not unique just to here."

Local agents investigate crimes from Waco to Brownsville, and all the way to Big Bend. Combs said agents have worked corruption cases across the entire region. However, some of the biggest cases they've recently investigated have occurred in towns and county's along the Texas-Mexico border.

"I think when you look at a number of the towns that are down by the border, there's certainly some poverty issues and that breeds corruption," Combs said. "Whether it's local, state and federal, we're looking at them all. Within the past two years, we've indicted people in each one of those levels. So it's not just a local or a county or a state problem, it's also a federal problem, as well."

The San Antonio FBI office has seen a steady increase in corruption cases. In 2012, it launched 23 investigations, 51 in 2013 and had 64 active cases in 2014.

Combs said when they go public with an investigation and indict people for their alleged involvement in corruption schemes, it often leads investigators to more corruption.

He said his office is looking into several tips that have come in since agents raided the homes and city offices of several officials in Crystal City earlier this year.

"We find that public corruption cases breed other public corruption cases, either through the subjects we interview then indict through the U.S. Attorney's Office and again from media coverage," Combs said. "When Crystal City happened, every media outlet here in South Texas covered that and we got a lot of phone calls about additional corruption plots going on in southern Texas."

From mayors and city councilmen, to police officers, anyone can be involved in a corruption scheme.

In 2007, FBI agents used court-authorized wiretaps to catch conversations between former Cameron County Judge Able Limas and an accomplice discussing how much he was expecting in payments in return for favorable rulings in his court.

According to the FBI, Limas "received more than $250,000 in bribes and kickbacks while he was on the bench."

Limas ultimately pleaded guilty to racketeering and was sentenced to six years. He cooperated with the FBI and helped them uncover "wide-ranging corruption in the Cameron County judicial system."

Combs said in most cases, corrupt officials often sell out for much less than Limas.

"It's not always just bundles of cash. Sometimes it's gifts, sometimes it's services in-kind, sometimes it's somebody gets a contract that's a family member. So there's various ways the corruption scam can work," Combs said. "I'm actually surprised when I look at a lot of the public corruption cases we've investigated with how small the monetary value is. It's hard for me to realize that someone would throw their life away and go to prison for a $1,000. So we're not even talking about huge sums of money here."

Combs said agents aren't focused on how much money is involved in a case. They're more concerned with the impact the corruption has on the communities.

"What's important is there is the violation of the public trust. So whether that's $100 or $100 million, if we feel there's a public trust that's been violated and we have to regain that public trust, we're going to investigate that crime," Combs said. "The key with public corruption comes down to money. It doesn't even make a difference the amount of money. It's just people who want an easy way out and taking a free ride to get some money. Greed is the bottom line. The color of corruption is green."

As his agents investigate new allegations of corruption, Combs had some friendly advice for anyone who may be involved.

"You want to come to the FBI before the FBI comes to you," Combs said. "There is no question that we are out there, we are looking to prosecute public corruption cases. So if you're involved, it goes a lot better for you if you come forward to us than if we come find you."

To report possible corruption to the FBI, call 210-225-6741.