He and his brother Brahim played a key logistical role in the wave of terror which left 130 people dead and hundreds injured, renting cars and hotel rooms where the jihadists could hole up.
Brahim, like another five of the assailants, blew himself up after the bloodshed. A seventh was shot by police.
However Salah did not. Instead he was spirited away to Belgium by two other men who were arrested and charged there.
On the night of the massacre, the jihadists arrived in a three-car "convoy" from Belgium, investigators have learned as they pore over CCTV footage, GPS maps and telephone surveillance.
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Investigators initially thought Salah was part of a "commando team" which drove through the east of Paris spraying cafes and bars with gunfire while another slaughtered 89 people at the Bataclan concert hall.
Another team blew themselves up outside the Stade de France where President Francois Hollande was watching a friendly match between France and Germany.
When Islamic State jihadists issued their claim of responsibility, their statement mentioned the assaults on the stadium, the 10th and 11th districts of Paris, but also the 18th, where no attack took place.
However four days after the police found a black Renault Clio, rented in Salah's name, parked partly over a pedestrian crossing in the 18th district.
Another was found outside the Bataclan, and another was found in Montreuil, a suburb just east of Paris.
All three Bataclan attackers died, and the car found in Montreuil is believed to have been used by ringleader Abdelhamid Abaaoud who was spotted at a nearby metro station.
Was he supposed to carry out an attack in the 18th?
The Obs news website reports that the two men held in Belgium say they found him in a state of shock and wearing an explosives vest when they came to spirit him out.