PARIS, Nov. 19 (UPI) -- Officials in France identified a second French citizen, 22-year-old Michaël Dos Santos, as one of the Islamic State militants shown in the execution video of American Peter Kassig.
The once-Roman Catholic son of Portuguese immigrants was identified by the Paris prosecutor's office Wednesday.
Both Dos Santos and fellow Frenchman Maxime Hauchard, 22, appear unmasked in a propaganda video released by IS -- which also uses the acronyms ISIS and ISIL -- showing decapitated aid worker Kassig.
Dos Santos converted to Islam and was well-known to anti-terror officials in France even before the release of the video.
French President Francois Hollande said his government would investigate the men's involvement in the terror group.
"We have to be even more aware, even in terms of the information that needs to be handed out, in terms of the danger that Internet sites carry and how these young people can be indoctrinated," Hollande said, speaking from Australia. "They could be from any background, from any ethnic origin, but they easily can be brainwashed into becoming converts."
