Police say the gunman who killed four hostages at a Paris kosher supermarket rented a small suburban house the week before and filled it with an impressive arsenal of late-model weapons.

A published report said a search of the house rented by Amedy Coulibaly has enabled police to identity a potential fourth attacker as investigators follow the money and supply systems for the three known killers, all of whom died in police raids.

French police officials refused to say what has been discovered inside the dwelling that Coulibaly rented. But the newspaper Le Parisien reported detectives from the Paris Criminal Brigade and a special police anti-terrorism unit seized a scooter there that allowed them to identity "a fourth man" who acted as Coulibaly's accomplice.