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OPA-LOCKA (CBSMiami) – Frank Zambrana may turn out to be the star witness in one of the biggest public corruption cases in South Florida, but for now he is a man lost in regret.

After trying to open a business in Opa-locka, Zambrana said he was shaken down for thousands of dollars in payoffs for his occupational license by City Manager David Chiverton, City Commissioner Luis Santiago and others.

“Everybody knows about this corruption,” he said. “Everywhere you go you hit a wall. We want to see an end to this.”

Three years ago he became a confidential informant for the FBI. He claims to have made hundreds of hours of video and audio recordings documenting the payoffs.

“Everything was on video; me, my voice, everything,” he said. “Mr. Chiverton counting the money. Santiago counting the money. Everybody was laughing.”

Zambrana agreed to reveal his role in the investigation out of frustration that nothing has happened.

“What is enough to put these people behind bars?” he asks. “What is enough to remove these people out of power? They go to work every day like nothing happened. These people should be removed from power. These people should be in jail right now.”

The FBI declined to comment on the status of the investigation.

Zambrana’s sorrow runs deeper. While he worked years with the FBI on this case, one of his sons, Andy, was dying of cancer. He said the fact that Opa-locka officials would shake him down while his family was in crisis is something he’ll never forget.

“They knew but they didn’t care,” he said.

The time he spent on the FBI case was time away from his son. And the fact that he couldn’t get a license to run his business meant he couldn’t provide for his family. The strain grew so intense, another of Zambrana’s sons, Christian, committed suicide.

“When Andy started going through pain, Christian couldn’t take it,” he said.

The guilt was overwhelming.

“I couldn’t take care of my sons,” he said.

Asked if he blames Opa-locka officials for what happened to his sons, Zambrana leans forward in his chair, his face tightening. “I don’t blame them for the death of Andy, I don’t blame them for the death of Christian,” he said. “But they deny me the right to take care of my family; they deny me the right to take care of my kid that was dying of cancer. By doing all these actions they deny me my right to be a father.”

After Christian’s death Zambrana told the FBI he didn’t want to continue working undercover any longer. By then he didn’t have the money to continue paying rent on the land he was leasing. As he was about to shut down his business, he said he was told his occupational license was ready to be picked up.

“I cannot describe to you how I feel,” Zambrana said, the disgust evident on his face. “I just, I got a piece of paper. Mr. Chiverton handed it to me, `Look, I finally got your license.’ Kind of laughing, `I got your license.’”

A short time later he closed his business for good, he said, “empty-handed, with no money in my pocket.”

He was so broke that when Andy died last year he said he had to borrow the money to pay for his funeral. A local charity stepped in and helped bury his son.

Zambrana said he wishes the FBI could have arrested someone before Andy died. He said he wanted to show his son that his dad actually accomplished something and the time he spent away from him meant something.

“I would have loved to see my Andy looking at the TV and see all these people getting arrested,” he said, the vision of it playing in his mind. “`Look son all these people are going to jail. Look son they’re not going to hurt nobody no more.’ But I guess my Andy didn’t have a chance to see that. I guess my Andy didn’t have the chance to see the end of this.”

Recently The Miami Herald published Zambrana’s story.

The day the newspaper came out I walked outside of my house and I put the paper to the sky like this, he said lifting his hands into the air, “and said, ‘Look son this is for you.’ I showed the paper to the sky and said, ‘This is for you son.’

Now that everyone knows he has been cooperating with the FBI, he admits to being worried about someone coming after him.

“I ask my sons every day, they’re my angels; I ask them to protect me,” he said. “I ask God to protect me. And I guess that’s the only protection I have right now.”