Claude Dubois, a former florist and her husband, retired maintenance worker Gérard, disappeared on 31 March 2011 while on holiday in the small town of Manuel Antonio, south of San José.
The couple checked into a hotel and did not return there after setting off on an excursion the following day.
Their hired car was found in the neighbouring town of Quepos, along with their rucksacks and sunglasses. Identity documents were found 75 kms away in a ditch.
Their bank cards were used on several occasions between 31 March and 7 April and 12,000 euro was spent on computer equipment, shoes and petrol.
Two men found in possession of the cards were questioned but later released.
Diario Extra, a Costa Rican daily newspaper, reports that the husband and wife had their cases stolen and were then killed and buried by a group of fake tourist guides.
Earlier this year, the couple’s family complained at the lack of progress in the police investigation and asked then-president Nicolas Sarkozy to push for greater co operation between French and Costa Rican police.