By Jack Douglas | CBS11

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DALLAS (CBS11) – The government laid out its case Tuesday in the federal corruption trial of Dallas County Commissioner John Wiley Price, with the lead investigator taking the stand.

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Former FBI agent Don Sherman, now hobbled by a stroke, said the bribery investigation began in 2010, with questionable bank transactions tying Price to political consultant Kathy Nealy and his county staff member, Dapheny Fain.

Sherman testified that Nealy wrote checks to Price totaling “tens of thousands, if not hundreds of thousands” of dollars.

In return, the government alleges, Nealy sold Price’s influence to companies seeking lucrative contracts with the county.

The former agent, who walked slowly to the witness stand with a cane, also said Price “moved money” between himself and a private business owned by Fain, the commissioner’s executive assistant.

After getting approval from the FBI’s Public Corruption Unit in Washington, Sherman said the government did a “tremendous amount of work” watching Price’s home, his cars and his financial transactions.

Another FBI agent later testified that nearly $230,000 in cash was found in a safe during a raid of Price’s home in the summer of 2011. Other items found at the home, testimony showed, included expensive cars, jewelry, watches, African artwork — with price tags still on them, custom suits and Italian-made shoes.

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Sherman described the FBI’s first encounter with Fain, saying that, at first, she was “calm and collected.”

But when Fain denied any connection between her private business and Price, the former agent said the FBI pressed her, with knowledge that bank records did show a link.

“She became more agitated and resisted in answering our questions,” Sherman said of the encounter, which took place in the Dallas County Administration Building.

He said Fain ended her meeting with the FBI by saying, “You’re just trying to trick me.”

Sherman’s testimony had long been anticipated, because of his dominate role in the investigation.

Fain’s defense lawyer, Thomas Mills, repeatedly questioned Sherman’s ability to recall accurate testimony, because of the stroke he suffered. Sherman responded, saying his memory was strong, and that any lapses of minute details were only because of the enormity of the probe and the time that has passed since it began.

Day 3 of the trial ended with testimony from FBI agent Monica Segedy, head of the agency’s raid on Price’s home on June 27, 2011.

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Testimony is expected to continue Wednesday morning, detailing items seized in multiple searches that day.