PARIS (AP) Karim Benzema's lawyer will take legal action against a radio station that published a transcript of a conversation between the France striker and a friend which was recorded as part of the investigation into a sex tape involving national teammate Mathieu Valbuena.

French radio Europe 1 violated the confidentiality of an official investigation, Sylvain Cormier told The Associated Press on Tuesday.

The extracts published on Monday tend to give credence to the claim that Benzema, who was charged last week with conspiracy to blackmail and participation to a criminal group, took an active role in the extortion scam.

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''This is a scandalous method,'' Cormier said. ''They did not publish the conversation in its entirety, but extracts of it. We believe that the files have been leaked to the press to influence Valbuena's future testimony.''

The investigation, which includes wiretap evidence, started when Valbuena decided to take legal action after being contacted by a man claiming to be in possession of an incriminating sex tape.

Benzema's involvement has yet to be determined, but investigators believe he was approached by a childhood friend to act as an intermediary. According to the transcript, Benzema tried to convince Valbuena to deal directly with the blackmailers.

Cormier has a different view, being adamant that Benzema was not involved, and that he tried to dissuade Valbuena from negotiating with the suspects.

Benzema, who spent a night in police custody, denies any wrongdoing. He has been placed under judicial supervision, meaning he cannot meet with the victim - Valbuena - or other people charged in the case.

According to a report from RTL radio, Valbuena has decided to become a civil party to the case and will be questioned next week by the investigating judge. The move means that his legal team will have access to the case files. Valbuena's lawyer, Didier Domat, was not immediately available for comment.

At least four other people have been handed preliminary charges in the case since October.