MIAMI (CBSMiami) – Broward prosecutors called their star witness Wednesday in ex-Hallandale Beach Mayor Joy Cooper’s corruption trial.

Alan Koslow, once a powerful attorney and lobbyist, says he introduced what he believed to be two developers to Cooper back in 2012.

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The developers were really undercover FBI agents and Cooper was involved in a contentious political race with Keith London.

“There were several meetings one in her office I recall,” Koslow told the jury.

Koslow was secretly captured on tape with Cooper meeting with the undercover agents at Gulfstream Park and a local diner.

Those tapes are being played for the jury.

Prosecutors say the agents, posing as developers offered Cooper campaign contributions in exchange for her vote on development projects.

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In court, prosecutors showed the jury cashed campaign checks with Cooper s signature.

“I found out in 2013 they were really FBI agents,” Koslow told the jury.

Koslow eventually began working with the FBI as a cooperating witness.

He pleaded guilty to money laundering and spent a year in prison. He admits to using cocaine and Cooper’s attorney says that calls his credibility into question.

“You have been using cocaine since 2004,” defense attorney Larry Davis told Koslow during cross-examination.

“Not continuously since 2004,” Koslow shot back.

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The trial resumes Thursday afternoon.