Rep. Richard Kelly (R-Fla.) took $25,000 from an FBI agent posing as a representative of oil-rich Arabs because he was investigating his own suspicions that his congressional staff had been infiltrated by persons who could destroy his political career, a federal court was told here yesterday.

Kelley, 56, who was a federal prosecutor and a state judge before he went to Congress in 1974, had to "seek out the truth on his own," his lawyer, Anthony L. Battaglia, told the U.S. District Court jury. Repeatedly referring to his client as "judge," Battaglia said that before Kelly got any answers, the FBI shut down what turned out to be its elaborate undercover operation known as Abscam.

On secret videotapes made last January in a luxurious house in Northwest Washington, the government says, Kelly is seen stuffing the $25,000, in $20 and $100 bills, into his jacket and pants pockets.

Kelly is on trial with two codefendants on charges that he conspired with them to get bribes from the Arabs in exchange for his influence in connection with immigration matters, including introduction of legislation on behalf of wealthy -- but, as it turned out, fictitious -- Arabs who supposedly wanted to come to this country.

Assistant U.S. Attorney Roger M. Adelman told the jury yesterday that the government's evidence would show that on Jan. 8, Kelly, his two codefendants and a fourth man were picked up in a limousine -- sent by the FBI -- at the Madison Hotel in downtown Washington and taken to a house on W Street NW. There, unaware that they were surrounded by FBI video and audio tape equipment, Kelly and the other men met with FBI undercover agent Anthony Amoroso and Melvin Weinberg.

Amoroso, who posed as a man called Tony Devito, and Weinberg, a convicted con man, swindler and FBI informant, were the key figures in the bureau's 14-month Abscam invetigation, which so far has resulted in the convictions of four members of Congress.

Adelman said in his opening statement that Kelly left the W Street house that night with the cash, handed over by agent Amoroso, and a fistful of cigars.

It had been a "good evening" said Adelman.

In his opening statement for the defense, Battaglia said that Kelly became concerned about his staff when he learned that his former executive assistant, J. P. Maher III, had introduced him to various people -- some of whom turned out to be convicted felons -- and had urged Kelly to go into business with them.

It was through Maher that Kelly met one of his codefendants, Eugene Robert (Gene) Ciuzio, who told Kelly about the Arabs who wanted immigration help, Battaglia said. At that point, Battaglia declared, Kelly felt that he had to go forward and pursue the information he needed to resolve his suspicions about his staff.

When Kelly was offered the money at the W. Street house by FBI agent Amoroso, Battaglia said, Kelly repeatedly resisted but finally felt he had to take the cash so "they'd trust him." Kelly, who was defeated for renomination to Congress, returned all the money to the FBI immediately after the undercover operation was made public last February.

Kelly is on trial along with Ciuzio and New York accountant Stanley Weisz. All are charged with conspiracy, bribery and interstate travel to facilitate a crime. Ciuzio had been a client of Weisz. CAPTION: Picture, Rep. Richard Kelly: accused of accepting $25,000.By James K. W. Atherton -- The Washington Post