An investigation in to handling of the Sophie Toscan Du Plantier murder case in Ireland has been launched by the Garda Ombudsman.
Ian Bailey lodged a complaint with the force watchdog in December just weeks after new files claimed the 15-year-old Garda investigation was flawed.
The one-time murder suspect, who was arrested and questioned twice by investigators, yesterday won a two-year legal challenge against his extradition to France for questioning.
His complaint focuses on recently released documents which included a 44-page critical review of the conduct of the murder investigation and the reasons why the former director of public prosecutions (DPP) decided not to prosecute.
The Department of Justice said once the existence of the 2001 review was brought to the attention of the Attorney General, Marie Whelan, and Justice Minister Alan Shatter, the documents were given to the solicitors and counsel representing all sides in the extradition proceedings, including the French authorities.
The material also questioned the credibility of several key witnesses and alleged an unnamed senior garda or gardai tried to get the former state solicitor for West Cork to put political pressure on the DPP to prosecute Mr Bailey.
Former DPP Eamon Barnes described the Garda investigation into the murder of Ms Toscan du Plantier as flawed and prejudiced, and the attempt by gardai to get a direction from the DPP's office to prosecute as grossly improper.
Mr Bailey's solicitor Frank Buttimer yesterday said had been surprised by political silence surrounding the documents, which have formed the basis of a complaint made to the Garda Siochana Ombudsman Commission.
The watchdog has extended its six-month time limit to examine a case and initiated an investigation.
Mr Bailey, 54, is also taking legal action against the State for wrongful arrest.
Mr Shatter said: "I believe that it is clearly desirable that these matters be investigated in the public interest and that the Ombudsman Commission is the appropriate body to do so."
Mr Shatter said he is also consulting with the attorney general over how the documentation only emerged after the proceedings were determined in the High Court, and only shortly before the hearing of the Supreme Court Appeal.
Ms Toscan du Plantier, 39, was found beaten to death outside her holiday home in Schull, west Cork, two days before Christmas 1996.
Under French law, authorities can investigate the suspicious death of a citizen abroad but they cannot compel witnesses to go to Paris for questioning.
Five Supreme Court judges upheld Mr Bailey's appeal against his extradition and ruled that under Irish law the former journalist could only be extradited to face prosecution, and not for questioning.
However authorities in Paris plan to continue with their investigation and could hold a trial in Mr Bailey's absence based on the evidence of Irish witnesses.