A witness in the trial of former finance minister Abraham Hirchson told the court yesterday that he gave Prime Minister Ehud Olmert a "fat envelope" at Hirchson's behest. The police are dubious of his version of events, though.

That aspect of David Cohen's testimony was new to the police, and law enforcement officials yesterday did not rule out an investigation into Olmert's alleged involvement. It will be up to Attorney General Menachem Mazuz to decide whether to investigate Cohen's allegations, the enforcement sources said.

The National Headquarters of the police stated, however, that the Hirchson case has already been investigated and they had decided there was no reason to suspect Olmert was involved.

"It is an outrageous allegation by a witness who knows that when he casts allegations on the witness stand, he's immune, so he isn't afraid to say things that are patently false," said a police source.

Cohen yesterday said that he did not know what the "fat envelope" contained.

He had worked as a messenger for the non-profit organization Nili and the National Workers' Organization. Hirchson stands accused of embezzling money from these organizations.

A spokesman for Olmert denied Cohen's version of events. "The police have already investigated the matter in depth, and found nothing to raise suspicions against the prime minister," media consultant Amir Dan said.

Cohen was convicted in a plea bargain Sunday of stealing NIS 5.5 million from the National Workers' Organization after falling into gambling debt. He was also convicted of serving as an accessory to the theft of another NIS 860,000 by other defendants.

During the trial, Cohen was asked how he knew the envelopes he had been asked to deliver to Hirchson contained money. He replied that one time, he had helped count the money and place it in an envelope, and that another time, the envelope had been torn, and he saw it contained cash. Hirchson has not denied taking money from the workers' organization, but said the money was given to him as part of his retirement benefits.