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.
Read more: Man arrested over Alps killings
More top news
Police in Beirut are investigating the sudden death of British embassy worker Rebecca Dykes, government sources said.
A tip from the CIA was sufficient to track down and detain a group of suspects planning to bomb the Kazan Cathedral and other sites.
The 12 Years A Slave director is filming an artwork as a 'lasting memorial' to the Grenfell Tower fire tragedy.