The Movement for Quality Government has called on Attorney General Menahem Mazuz to block the appointment of Yisrael Beitenu leader Avigdor Lieberman to the post of Internal Security Minister, Army Radio reported. According to a legal expert, Lieberman could be legally barred from accepting the Internal Security portfolio while there is an open police investigation against him, according to a legal expert. The police have yet to close a case involving alleged corruption and illegal business dealings against Lieberman from eight years ago. The case has moved from the police to the State Attorney's Office, which will decide whether it has any basis. Lieberman ran his election campaign focusing on safety and crime, and has set the Internal Security portfolio as his price for entering the coalition. Interim Prime Minister Ehud Olmert appears to be favorably weighing the request. But a 2004 High Court of Justice ruling regarding the ability of former internal security minister Tzahi Hanegbi to remain in office while under investigation could apply to Lieberman as well, according to Suzie Navot, who teaches parliamentary and constitutional law at the College of Management in Rishon Lezion. "Lieberman is a problem because the case is still open," Navot told The Jerusalem Post. She said that until the case is closed, Lieberman's appointment is likely to be blocked either by the High Court or the attorney-general. The court was split 4-3 on the Hanegbi issue, she said. Four justices suggested that it would be better for Hanegbi to leave the ministry while the other three ruled that according to the law he had to resign, she said. What's important is that all the justices believed that a politician who is under a police investigation "cannot serve as minister of internal security because he is in charge of the officers that are going to investigate him," she said. At the time, it was hard for the justices to insist that Hanegbi must leave because he was already in office, and it is difficult to strip a minister of his title, she said. But that same concern does not apply when it comes to the appointment of a minister, she added. Until the police investigation is closed, Mazuz could use the Hanegbi case as a precedent to stop Olmert from appointing Lieberman to the post, she said. It is also likely, she said, that if a petition were filed against his appointment, the High Court would prevent him from taking office. The Justice Ministry and Lieberman's office had no comment on the matter. Historically, police charges have been used to bar politicians from taking the Internal Security portfolio. Attempts in 1996 by former prime minister Binyamin Netanyahu to appoint Rafael Eitan as Internal Security minister were foiled by a police investigation which was later tossed out of court.