In November, police released an image of a male motorcyclist they wanted to speak to in connection with the killings.
The French Gendarmerie released an artist's impression of a motorcyclist who was seen riding in the area shortly before the four murders took place.
The man's helmet was said by Mr Maillaud at the time to be "very particular" and one of only a few thousand models worldwide, with a bottom section which opened laterally to reveal the lower face.
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Police investigating the disappearance of a British toddler in Germany more than 35 years ago have released an image of a suspect.
Lord Stevens said drones should be prohibited near sensitive sites like airports.
The strike action was due to begin on Wednesday.