In its relentless pursuit of tax-evading gamblers at West Virginia race tracks, the Internal Revenue Service took a little gamble of its own.

Having obtained solid evidence against one "10 percenter" who had violated tax laws, the IRS brought two innocent men to trial along with him, attempting to get three convictions for the price of one.

To get those convictions, four IRS agents attempted to spin a web of circumstantial evidence and half-truths around Lynn Largent Sr. and Youelle (Willie) Logan in testimony at U.S. District Court here.

But a jury of eight men and four women wouldn't let the government get away with it. While convincing Michael H. Cohen, they pronounced Largent and Logan not guilty yesterday afternoon, after a two-day trial that left the impression that the IRS methods were as despicable as any of the crimes the defendants were charged with.

The Internal Revenue Service takes a special interest in the West Virginia tracks, because their gimmick bets, such as the Big Exacta, often produce large payoffs requiring the winner to fill out a tax information form. IRS agents suspected that Cohen, known to his fellow race trackers as "Heavy," would cash these tickets for a fee so that the real winners could keep their identity hidden from the government.

Four agents were watching Cohen in the Shenandoah Downs clubhouse on the night of March 17, after the Big Exacta had paid $846.40. They saw Joseph Workman, a Fisherville, Va., funeral director, handled a Big Evacta ticket to cohen, who took it to the cashier's window and returned with the money, minus a fee. They also saw largent and Logan have transactions with Cohen.

When the agents later interrogated Workman, Largent Logan, only Workman admitted he had illegally turned over a Big Exacta ticket to Cohen. Yet Workman was the only only one who was not charged with any offense; he appeared in court only to testify against Cohen. But the agents chose to disbelieve the other two men, despite the credibility of their stories.

Sixty-two years old, soft-spoken, silver-haired, a respected businessman, Largent was the very antithesis of a suspicious race-track character. He had told the agents months ago, as he testified this week, that he played the Big Exacta in partnership with an elderly oriental man whose name he did not know. After they won, the stranger volunteered to cash the ticket and fill out IRS Form W-2-G. (Even if a ticket is jointly held, only one winner may sign the form).

IRS agent Larry Mincks, testified that he saw Largent and "an elderly gentleman of oriental descent" discussing their Big Exacta tickets (though the prosecution would later refer to the "phantom oriental").

Largent collected his share of the Big Exacta from the man, and a few minutes later spotted Cohen, whom he owed $20. The defense submitted as evidence part of a notebook in which Largent kept track of his debts, and his repayment of them. It read in part:(TABLE) Mr. Fox(COLUMN) $5(COLUMN)Mar 25 Short colored man(COLUMN) $5(COLUMN)Mar 17 Heavy(COLUMN)$20(COLUMN)Mar 17(END TABLE)

Largent handed "Heavy" a $20 bill. Yet three IRS agents who saw the transaction swore they had seen Largent turn over a Big Exacta ticket. The trial turned on their perceptions.

Agent John D. Moore testified that he could recognize the ticket (about an inch long) from a distance of 15 feet. Could he identify Largent again? He looked at the defendant and said, "He's the man in the gray suit."

Largent was wearing a brown suit. He was sitting about 15 feet away.

Then Cohen's attorney, Richard White, held up an object and asked, "Mr. Moore, is this a Big Exacta ticket?"

"Yes," Moore testified.

White walked closer and held the ticket near Moore's face. "Is this a Big Exacta ticket?" he repeated. "No," the agent conceded.

The agents would have needed Superman's powers of vision to swear for certain that what Largent handed Cohen was a ticket. And their testimony seemed just as doubtful when they tried to incriminate Logan, who said his only transaction with Cohen occurred when he borrowed five dollars from him.

"The agents went to the track looking for a crime," Logan's attorney, John Henning, told the jury. "That is their slant. Many times what you see is slanted by what you expect to see . . .

Anyone who approached Mr. Cohen on the night of March 17 would immediately become a suspect."

Anyone who had dealings with Cohen would not merely be suspected by the IRS, said Largent's attorney, David Martin. He would be presumed guilty.

"Our system of government is supposed to guarantee a presumption of innocence, but the IRS assumes a person owes taxes and wants him to prove that he doesn't," Martin told the jury. "This attitude carries over to criminal cases. If you had innocent dealings with Michael Cohen, and you had not told the IRS agents the story they wanted to hear, you would be sitting where Lynn Largent is."

The jury evidently agreed.