While he was being investigated for criminal ties to Northern Virginia's flourishing bingo games. Alexandria prosecutor William L. Cowhig was advising a major figure in the probe how to avoid helping the investigation, according to a transcript of a telephone conversation filed in state court.

Cowhig's advice to Edward L. Hinkle came in a secretly recorded telephone exchange that occurred June 26, a month before Cowhig was indicted on charges of accepting bribes and gambling in the bingo operations. Cowhig has since taken a leave from his public office pending his trial next month.

"You can take the Fifth Amendment so to speak," Cowhig told Hinkle in a conversation that was taped, with Hinkle's permission, by Alexandria police officials. ". . . You say you're under investigation by the local police, reference to bingo, . . . and that you're not going to testify to anything," Cowhig said.

Cowhig, 53, Alexandria's commonwealth's attorney, is a lifelong friend of Hinkle, the co-owner of a real estate company that leased auditoriums to bingo sponsors in the Northern Virginia area. Hinkle has not been indicted in connection with the bingo probe and the transcript filed in Alexandria Circuit Court indicates he may have been cooperating with the investigators.

At the time of the alleged conversation, Hinkle had been subpoenaed to testify before a federal grand jury investigating allegations of interstate racketeering, gambling, and official corruption in Northern Virginia.

A copy of the telephone transcript was placed in court files by special prosecutor Edward J. White in response to requests made by Cowhig's attorneys, who have said they need to know details of the charges against their client. Cowhig, the first incumbent commonwealth's attorney ever indicted in Virginia, is due to stand trial on the bribery count on Dec. 5.

Cowhig also counseled Hinkle in July to limit his testimony to matters involving the rental fees charged for the use of his bingo hall, according to the transcripts. "Well, I wouldn't say anything except about the rent. Nobody knows anything about (that) and that's all your involvement is anyway . . ." Cowhig told Hinkle in a taped telephone conversation on July 6.

Cowhig has repeatedly asserted he is innocent of the bribery and gambling charges he faces.

Leonard B. Sussholz, one of Cowhig's defense attorneys, said yesterday the court papers may be an attempt "to stimulate adverse publicity."

Sussholz also said that his client informed him that Hinkle was an informant for the commonwealth's attorney's office. "Cowhig told me he (Hinkle) used to be a snitch for them," Sussholz said, adding, "There are gross inconsistencies in the papers." The attorney also said White failed to provide dates and times of the alleged bribes.

More than 100 pages of telephone conversation transcripts> witness lists, financial records, and letters to and from the principals in the bingo investigation were placed into the public record by White. The documents lay out the case he is expected to present against Cowhig with regard to the charge that Cowhig solicited and received $34,000 in bribes at the rate of $500 a week for 68 weeks from Dirgham Salahi.

Salahi, who is director of the Montessori School of Alexandria, has been granted immunity from prosecution in exchange for his testimony, and is expected to be a key witness at the trial. The school operated one of the most profitable bingo games in Alexandria at the time.

Salahi, paid the money to Cowhig "to buy peace" for his bingo operation prosecutor White alleges in court papers.

"The defendant's purpose was apparently to enrich himself, the special prosecutor said.

"The defendant (Cowhig) exercised his discretion as commonwealth attorney by ceasing his pursuit of alleged wrongdoing on the part of the Montessori bingo, which he had hitherto expressed forcibly on several occasions," according to court papers.

Details of the alleged payments were also listed in White's court filing. The money - cash only - was passed from Salahi to Cowhig on a weekly basis from Jan. 4, 1977, to May 1, 1978 - weeks after Cowhig himself had called for a special bingo prosecutor, according to White.

The two men met at the Montessori bingo auditorium at 350 S. Pickett St. "mainly on Sundays," White alleged.

The meetings later shifted to the Montessori School on N. Pitt Street in Alexandria and other locations, including Cowhig's City Hall office, White charges.

At the same time he was pav'ng Cowhig, court papers say, Salahi was allegedly taking money from bingo proceeds that should have gone to one of the games' charitable sponsors, Ascension Academy, a private Alexandria school.

White alleges that Salahi tape-recorded his meetings with Cowhig, but then destroyed the tapes at Cowhig's direction in May 1978.

But the special prosecutor also revealed that Salahi initially denied to investigators that he had paid money to Cowhig. Ten days later - on July 17, 1978 - Salahi "changed this statement and admitted that he had paid the defendant money . . ." White alleges.