Paris prosecutors are investigating allegations that Mehdi Nemmouche was part of a islamist group that held four French journalists hostage in Syria last year, an unnamed judicial source told Reuters news agency, reports FRANCE 24.
The probe, launched in July, relates to kidnapping and terrorism charges, Reuters reported in an article published Friday.
Nemmouche, a Frenchman of Algerian descent, is already being tried in Belgium for killing four people during a shocking attack on the Jewish Museum in Brussels in May 2014.
Edouard Elias, Didier François, Nicolas Henin and Pierre Torres were freed in April 2014 after 10 months in captivity.
François, a veteran war correspondent, and Elias, a photographer, were abducted in early June 2013 on their way to Aleppo in Syria. Hénin, who was working for Le Point magazine, and Torres, reporting for French-German television channel Arte, were taken later that same month near Raqqa.
The four men were held hostage together in basements and frequently had no access to natural light for their entire captivity. François told Europe 1 that the men were chained together for two-and-a-half months.
Hénin, said that Nemmouche, 30, would beat him and he had often heard him torturing Syrian hostages.