The wife of the Paris supermarket gunman may be in Syria, police sources have said.
Hayat Boumeddiene, 26, is partner of Amedy Coulibaly, who killed a policewoman and then four hostages at a kosher bakery.
A police source said she flew to Turkey via Madrid on January 2, despite alleged sightings of her in Paris on Thursday.
Authorities in Istanbul then reported seeing a woman matching her description cross the Turkey- Syria border on Thursday, the day her husband killed policewoman Clarissa Jean-Phillipe.
Sources say she had a return ticket from Istanbul to Madrid for yesterday but failed to show for the flight.
Police were today interrogating the wives of the Kouachi brothers responsible for the Charlie Hebdo massacre in a bid to track down Boumeddiene.
Hundreds of phone calls between Boumeddiene and Izzana Hamyd, wife of Cherif Kouachi, have shown up on mobile records. Five hundred in all were made last year.