The jury in the gambling trial of Alexandria Commonwealth's Attorney William L. Cowhig was sent home after four hours of deliberations last night by Circuit Court Judge Percy Thornton Jr.

"Your honor, I don't believe we can make a decision in the next few hours," said jury foreman Maurits Roos, after Thornton had asked the jury about its progress. The jurors departed the Alexandria courthouse at 8:05 p.m., and will resume at 9 o'clock this morning.

Cowhig, 53, is accused of organizing and operating illegal bingo games on behalf of B & J Specialties Inc. from March 1 to Sept. 1, 1977, at a bingo hall at 4603 Duke St. If convicted, Cowhig could receive five years in prison and a $1,000 fine.

Special prosecutor Edward J. White called 13 witnesses and chief defense attorney Blair Lee Howard called 11 witnesses druing the three-day trial in Alexandria Circuit Court.

Cowhig was acquitted in December of bribery charges in connection with unrelated bingo games. He faces trial on an additional gambling charge on March 5. Cowhig is the first Virginia commonwealth's attorney to be indicted while in office.

B&J Specialties is a private, for-profit company Cowhig helped establish in 1972. Its owner, Jame R. Fike, has also been indicted in connection with th same events, and is scheduled to stand trial next month.

In closing arguments yesterday, White told the jury that Cowhig had "covered up... an illegal gambling operation run by a phony company... he had been a part of since 1972...

"He had a piece of the action," White said, raising his voice for the first time in the three-day trial.

Howard countered that Cowhig, "a lieftim resident of Alexandria... and a dedicated commonwealth's attorney," had been "used" by two prosecution witnesses who lied to keep from being charged themselves.

"They used Billy Cowhig, they set him up, he was their trump card, their ace in the hole, Howard said, referring to Allen Palmore and Robert B. Hinkle. Each had testified for the prosecution about Cowhig's alleged role in organizing and running the bingo games.

Having "used" Cowhig, Palmore and Hinkle then "conned" White into bringing charges against Cowhig, Howard said.

The case turned on whether Cowhig had been an "operator" of the bingo games, which Judge Thornton told the jury were illegal "as a matter of law" since B&J. Specialties Inc. Was not permitted to operate bingo games because it was not a charitable organization.

White, in his closing argument, said for the first time in the trial that the games grossed as much as $56,000 each month between March 1 and Sept. 1, 1977, the period covered by the indictment, and netted at least $51,000 during that time.

White recalled that Jack Echols, a bingo caller, testified Cowhig told him he would be paid $25 a night, just as he had been paid for other bingo games at the same location. White also cited testimony by Hinkle that at a meeting at Cowhig's home, Cowhig had told Hinkle that Hinkle would be the manager of the games. Another witness, Henry Boggess, testified that Cowhig pointed out to him people who needed to buy bingo cards, White said.

Such actions "are what we mean by being an operator," White said. "And then there's Al Palmore." Palmore, a former manager at the Duke Street location, had testified that one evening he handed Cowhig an envelope stuffed with between $1,000 and $2,000 in $20 bills.

Howard and defense attorney James Clark attacked Hinkle and Palmore as "liars" who had received immunity for their testimony, and questioned Boggess' ability to remember events.

Howard told the jury of eight women and four men that Cowhig had invited B&J's operators to his home to explain Virginia's bingo law to them. Howard said Cowhig had met with those operators a second time shortly before the bingo games opened and often was present at the games in his official capacity as a prosecutor.