Former Alexandria bingo prosecutor Edward J. White has endorsed Commonwealth's Attorney John E. Kloch for election to the post because of what White termed "unalterably cheap shots" directed at Kloch by his two opponents in the race.

At a press conference this week, White sharply criticized Republican Barry Poretz and Independent John E. Kennahan for attempting to link Kloch, a Democrat, to the bingo scandals that resulted in the indictment and eventual acquittal of Kloch's predecessor, William L. Cowhig.

As the race has heated up in the past month, all three candidates have campaigned as much against Cowhig as they have each other.

Kloch served as Cowhig's chief deputy from the time Cowhig took office in 1973, and was appointed to replace him when Cowhig resigned earlier this year. Kloch, Portez and Kennahan are seeking the remainder of Cowhig's term, which expires in 1981. The election is Nov. 6.

"I resent these allegations by Poretz and Kennahan that they are going to 'clean up' that (prosecutor's) office," White said in announcing his support for Kloch. "Early on, I directed the Alexandria Police Department to investigate that entire office. They were convinced, and I was convinced, that no one knew anything about (any bingo activities)" except Cowhig, White said.

On the contrary, White said, "the mud is on their shoes. Portez represented one of the figures involved in the bingo investigation, and Kennahan is being supported by two of Cowhig's biggest backers."

Poretz once represented Robert Gerber, co-owner of a company that leased an Alexandria bingo parlor where illegal gambling allegedly took place. Kennahan is being supported by attorney Leonard B. Sussholtz, one of Cowhig's attorneys at his first trial.

Cowhig was acquitted of bribery and illegal gambling charges in two highly publicized trials. A third charge against Cowhig was dismissed in return for his resignation in February.

Poretz immediately branded the endorsement "the last gasp of a dying (candidate). The public does not have faith and confidence" in Kloch.

Kennahan also attacked White's contentions.

"I continue to draw the same inferences from the facts I know," Kennahan said, "that John Kloch knew or should have known what was going on in the office. He should have resigned to criticize that office."

Kloch countered that his resignation "would have served no useful purpose. It was more important that I keep things running smoothly."

He added that he had not sought White's endorsement, but "Ed White knows more about the bingo scandals in this town than anyone else."

White served as special bingo prosecutor from April 1978 until earlier this year. He said he decided three weeks ago to hold the press conference after the question of Kloch's knowledge of Cowhig's activities became the focus of the increasingly bitter campaign.

"Cowhig shared his thoughts with only a few people," White said, indicating that Kloch was not among these people.

"When Cowhig appeared to be using his office to cover up his activities," White said, "Kloch came to me and expressed concern about keeping the office running."