The Canadian authorities should interview Aaron Yoon on his return home from his imprisonment in Mauritania (which may take place soon) and keep a close eye on him thereafter. But his conviction in Mauritania on terrorism-related charges cannot simply be taken as proof that he is guilty of terrorism. And at present, it would be a stretch to hold an investigative hearing to compel him to give testimony, or to charge him with a crime.
Mr. Yoon, a Canadian from London, Ont., is a convert to Islam, who travelled to northwest Africa with two of his friends, Xris Katsiroubas and Ali Medlej. The other two undoubtedly went on to take an active part in an especially gruesome terrorist attack on a gas plant in Algeria, in which 37 hostages died, as did the two Canadians and many others among the attackers.
The RCMP should ask Mr. Yoon what he knows about when – and how – his two friends made contact with an al-Qaeda faction in the region. His answers – if he answers – could be highly informative about the radicalization of young Muslims who have grown up in the Western world.
A practical precedent for a conversation with Mr. Yoon was the interview of Abdullah Khadr, a member of a family at least some of whom were deeply involved with al-Qaeda, on his return to Canada in 2005. Detective Inspector Konrad Shourie of the RCMP spoke with Mr. Khadr for 21/2 hours, on a voluntary basis, at Pearson Airport in Toronto; Mr. Khadr waived his right to counsel.
Aaron Yoon’s return to Canada offers some promise of a better understanding of how extremist jihadism takes shape in Canada; so far, the prospects of gathering evidence from Mauritania for an extraterritorial prosecution appear tenuous.