French prosecutors have appointed a magistrate to investigate allegations concerning presidential candidate Francois Fillon and his wife in a scandal over public money she received for work she may not have done.
The prosecutor's decision to open up a new stage in the case on Friday marks a blow for Fillon, whose status as favourite to win the presidency has faded since a newspaper first reported the "Penelopegate" affair, named after his British wife.
By involving a magistrate in what had so far been a preliminary probe led by police, the prosecutor is putting more resources into the investigation. The magistrate has more powers to investigate, including tapping phones or placing suspects under house arrest.
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The judge can still decide to drop the case, place the suspect under formal investigation, or send it to trial.
It remained unclear if the probe could be concluded before the presidential election, scheduled for April 23 and May 7. Fillon has denied any wrongdoing and says his wife was paid for genuine work as his parliamentary assistant.
Under French law, the investigation would be suspended for the five-year presidential term should Fillon be elected.
The prosecutor's statement, which added it was examining possible misuse of public funds and a lack of full and proper disclosure, was issued as Fillon took to the stage at a campaign rally near Paris.
Fillon has pledged to stay in the race come what may, after saying for weeks that he would step down if he were put under formal investigation.