Wire-tap evidence used to obtain search warrants that led to charges in an alleged Quebec gas price-fixing scheme suggest discussions about prices took place in several regions beyond those targeted in a Federal Bureau Competition crackdown last month.

According to documents obtained by the CBC's French-language network, several gas retailers in Montreal, Trois-Rivières, Valleyfield, Sorel, Le Gardeur and Saint-Hyacinthe allegedly discussed fixing gas prices with competitors in other regions where charges of price collusion were laid.

The documents include telephone call transcripts between some retailers accused in the June crackdown, and other merchants who were investigated during the bureau probe, but not charged.

Thirteen people and 11 companies in total were charged in the investigation, and accused of illegally fixing gas prices in Victoriaville, Thetford Mines, Sherbrooke and Magog.

The transcripts in question were submitted as evidence to obtain search warrants in the investigation, said Donald Plouffe, an officer with the federal agency.

"It's certain that when you investigate, you obtain information," he told the French-language network.

"There were a series of conversations, discussions that … that certainly raise questions."

Discussions about price-fixing would be just one element of evidence among several needed to make formal accusations, he added.

It's necessary to establish whether there were "discussions between possible competitors, agreements, and [also] whether those agreements had an important effect on the market," he explained in French.

The bureau is still considering whether to press more charges in the investigation, Plouffe said.

The allegations haven't been proven in court. The parties return to court in the fall.

3 companies pleaded guilty to charges

A three-year investigation involving wiretaps, informants and undercover agents led to the June charges.

The bureau alleges the gas retailers were calling each other to agree on gas prices.

Three companies - Les Pétroles Therrien Inc., which operates under Pétro-T, Distributions pétrolières Therrien Inc. and Ultramar Ltd. - and one person pleaded guilty in Quebec Superior Court after the investigation was made public in June.

They were fined a combined total of more than $2 million.

Former Ultramar employee Jacques Ouellet was fined $50,000 after pleading guilty.

At the time of the charges, Competition Bureau commissioner Sheridan Scott said an "overwhelming majority" of businesses in the markets involved are accused of participating in the alleged scheme.

The bureau said it's difficult to calculate how much the alleged price fixing cost consumers.

Quebec motorist sues companies

A class-action lawsuit is pending in Quebec court after a motorist took legal action against several of the retailers accused of fixing pump prices.

Documents seeking permission to sue were filed in court in June, after the Competition Bureau announced the charges.

People who sign on won't likely receive large amounts of money, and the case could take years, said Quebec City lawyer David Bourgouin, who is handling the lawsuit.

The case was launched by an unidentified Quebec motorist.