A judge has declared a mistrial in Tony Accurso's fraud case.

Judge James Brunton made the ruling Friday morning after learning one of the jurors had received information about a Crown witness.

On Tuesday, one juror learned something about former engineer and political fundraiser Marc Gendron that was not disclosed at the trial, and shared that with two other jurors.

The juror told the judge on Friday that one of her relatives worked for Gendron, and this week the uncle told her about how he had once spotted a briefcase full of cash in Gendron's office.

She then told two other jurors what her uncle had said.

Gendron was an engineer who had worked for Tecsult, and was the only witness who said that Accurso had been directly involved in handing over kickbacks in exchange for rigging contracts in the city of Laval.

He told the Charbonneau Commission that he routinely collected bribes, picking up hundreds of thousands of dollars each year for then-Laval mayor Gilles Vaillancourt and was once given $200,000 in cash from Accurso himself.

Gendron was the only witness to testify to a direct link between Accurso and cash bribes.

Throughout the trial, Accurso denied having any involvement in the day-to-day operations of his companies, and said he was ignorant of any contract-rigging scheme.

Brunton said he had no choice but to declare a mistrial because the jury had been contaminated.

The trial was in its final phase, with the Crown supposed to make its final arguments on Friday, and the jury had been told they would begin deliberating next Wednesday.

The ruling means a new trial will have to be scheduled, with all witnesses testifying again before a new jury.

"We will be ready to fix a new court date. We will be ready in January," said Crown spokesperson Jean-Pascal Boucher.

"The fight is not over yet and our prosecutor they were at the end of the trial and they will be ready to fix the trial, to begin a new trial, in front of a new jury."

Brunton said this is the first time in his 15 years on the bench that he has had to declare a mistrial.

Originally the Accurso trial was supposed to last several months, but it wrapped up much quicker than expected when the Crown slashed its list of expected witnesses.

Accurso is accused on five counts: breach of trust, fraud, conspiracy to commit corruption in municipal affairs, conspiracy to commit fraud, and corruption of municipal officials.