A second French jihadist, Salim Benghalem, has been named as a possible captor of Western hostages in Syria, a source close to the case told AFP on Friday.
Benghalem was named along with Mehdi Nemmouche, who carried out a fatal attack on the Jewish Museum in Brussels last year, as suspected "jailers" for the Islamic State group (ISIS).
They are thought to be among the captors who held several Western journalists and NGO workers who were later executed, as well as four French reporters who were freed in April 2014 after 10 months in captivity.
A report in Le Monde newspaper on Friday cited a French intelligence source saying Benghalem was "currently part of the Islamic police of IS and participated in executions and corporal punishments."
One of the French journalists who was released, Nicolas Henin, spoke last year of being mistreated by Nemmouche during his detention, but Benghalem was never named.
Benghalem, 35, is listed as a "foreign terrorist combatant" by the United States, and is known to French intelligence services for his "active participation in combat" in Syria, according to the security source.
He came to the attention of French authorities for his involvement in the Buttes-Chaumont network of would-be jihadists in Paris that included Said and Cherif Kouachi, who carried out the attack on Charlie Hebdo magazine in January.
Benghalem was imprisoned in 2007 for his part in gang violence, and was released in 2010, after which he is thought to have traveled to Yemen, a security source said.
Nemmouche is awaiting trial in Belgium for the attack on the Jewish Museum which left four dead.