Israeli Attorney General Yosef Harish said today that a police investigation has begun into the Shin Bet security service's alleged cover-up of the 1984 beating deaths of two captured and handcuffed Arab hijackers and will continue regardless of the outcome of court challenges to presidential pardons given to security agents involved.

Harish, speaking at a High Court of Justice hearing on petitions to overturn the controversial pardons granted to the former Shin Bet chief, Avraham Shalom, and three of his aides, said that the police will investigate all levels of government, from administrative clerks to the highest officials.

Arguing that there is no need for the court to rule on the pardons because an investigation already has begun, Harish said the pardons could make the police probe more efficient because all security agents involved would be summoned as witnesses anyway. He said no witnesses had yet been summoned.

After hearing arguments from both sides, the three-judge court said it was reserving judgment for several days of deliberations.

The outcome of those deliberations is considered crucial to the entire case because if the blanket pardons issued by President Chaim Herzog, granting immunity from prosecution, are upheld, junior security service agents who actually participated in the killings also could be expected to apply for pardons. Having pardoned Shalom and his aides, it has been argued, Herzog would find it difficult not to pardon subordinates.

In that case, argued attorneys for several civil rights groups that today challenged the original pardons, any investigation would be meaningless.

Shalom, who resigned as Israel's top domestic security official, has been accused by three other former aides of ordering the killing of the Arab prisoners after they were captured in a bus hijacking in the Gaza Strip on April 24, 1984. He was also accused of directing a cover-up that involved perjury, suborning witnesses and falsifying evidence in two civilian inquiries and an internal Shin Bet disciplinary hearing.

The affair has threatened Israel's fragile coalition government because of the insistence by Prime Minister Shimon Peres' Labor Party that a formal judicial commission of inquiry be formed. The broader judicial probe, which could have investigated the role played during the alleged cover-up by then-prime minister Yitzhak Shamir, was opposed by Shamir's rightist Likud bloc and narrowly rejected in a Cabinet vote last week.

Although Peres has insisted that he wanted a judicial inquiry only to maintain secrecy around sensitive security matters, the affair has been dominated by political undercurrents because Shamir is scheduled to take over as prime minister on Oct. 25 under the coalition rotation agreement.

Police Minister Haim Bar-Lev said in an interview today that the police investigation will maintain as much secrecy as a judicial inquiry would have.

"The police itself will not issue any information and will not leak a single word. Of this I am 100 percent sure," said Bar-Lev, a Labor Party minister. "The military censor will keep an open eye on it, and I'm sure that he will prevent the publication of details that are security details."