The jury in the bribery trial of Alexandria prosecutor William L. Cowhig began deliberating yesterday after hearing more than three hours of emotional closing arguments punctuated by accusations of imporprieties between lawyers in the case.

At 12:50 this morning, after deliberating more than 10 hours, the jurors reported they were deadlocked, but returned to the jury room after Circuit Court Judge Percy Thorton told them to continue trying to reach to verdict.

Asked for a report by the judge at 2 a.m., the jurors said "substantial progress" was being made toward a verdict, then resumed deliberations.

Earlier, as opposing lawyers completed their arguments, Cowhig, the first Virginia Commonwealth's attorney indicted while in office, had sat at the defense table in the courtroom, his eyes sometimes filled with tears.

The seven men and five women jurors began deliberating at 2:10 p.m. as attorneys, reporters and friends of the defendant waited in the hallways for a verdict.

Tensions among those waiting for a verdict grew as the jury continued its deliberations early today. Shortly after midnight, defense concounsel Leonard B. Sussholz had a dispute in a hallway with special presecutor Edward J. White that ended with Sussholz striking White on the shoulder, according to witnesses. State police moved between the two men.

Earlier, another defense attorney, William B. Moffitt and State Police investigator Coy Ivy scuffled in the hallway.

Cowhig, 53, is charged with asking for and receiving $32,000 in bribes from Dirgham Salahi, director of the Montessori School of Alexandria, between Jan. 4, 1977, and May 1, 1978.

According to the indictment handed down last Aug. 3, Cowhig failed to prosecute Salahi for running allegedly illegal and highly lucrative bingo games to raise money for the school.

The Cowhig trail, which began Dec. 5, is the most serious legal proceeding to arise since allegations of improprieties in the city's $1.2 million bingo games surfaced last year.

Each side in the trial presented key witnesses whose credibility, the trial lawyers agreed, would be crucial to the outcome. They included Salahi for the prosecution and Alexandria accountant Frank Higdon, a defense witness who analyzed Cowhig's personal finances.

Attorneys for both sides delivered unusually heated closing arguments to the jury, frequently shouting as they reviewed the case and tried to discredit their opponents.

Special prosecutor White was labeled "a power hungry young man . . . running for governor" whose case against Cowhig "stinks." White, for his part, said Cowhig "kept his hands in his pockets and kept them warm with hot cash . . ."

Attacking the credibility of Salahi, a key prosecution witness, defense lawyer Louis Koutoulakos said, "The only bribe in this case was the immunity from prosecution given to Salahi."

Koutoulakos called the evidence presented by the prosecution "garbage."

"The case stinks," said Koutoulakos, during the 90-minute presention by the defense. "(Salahi) deliberately set up this man, (seeking) the destruction of one of the most decent people in the city of Alexandria. The Prosecutor needed a scapegoat, but could you send a man to prison on the evidence of an admitted lair?"

Salahi testified last week that he had once lied in a police report when he denied bribing Cowhig. Salahi was the only witness to testify that Cowhig had received the bribes.

Koutoulakos and cocounsel Sussholz also attacked State Police investigator Ivy, who had testified for the prosecution that Cowhig's financial obligations often exceeded his spendable income by as much as $2,000 a month.

Sussholz asked the jury to "forgive" both White and Ivy.

White told the jury that Cowhig was a man "who was broke" and who needed enormous sums of cash to cover the mortage on the Two Turtles, a small resort hotel Cowhig owned in the Bahamas, and two airplanes he bought.

"He kept his hands in his pockets and kept them warm with hot cash, . . . once the deal had been stuck," White told the jury.

Salahi "got what he paid for - there was no criticism (from Cowhig), no investigation, no nothing during the 16 months he was paying the money," White said.