Keeping tabs on convicted or suspected terrorists poses a major challenge for intelligence agencies, security experts are saying in the wake of the attacks in Paris this week that left more than a dozen people dead.
More details are emerging about the two brothers believed to be responsible for the deadly attack on the offices of satirical newspaper Charlie Hebdo on Wednesday, but authorities have already linked both men to previous terrorist activity.
Prior to Wednesday鈥檚 attack, Said Kouachi was suspected of having fought alongside al Qaeda militants in Yemen, while younger brother Cherif Kouachi was found guilty in 2008 for his ties to a group that sent fighters to join militants in Iraq.
An official said Thursday that the brothers had been placed on the U.S. no-fly list and were known to American counterterrorism authorities.
French authorities say the men were killed during a shootout with police Friday, following a hostage-taking at a printing house located north of Paris.
In Paris, a gunman named Amedy Coulibaly killed four people after entering a kosher market. He later died in a police raid.
In an interview with 麻豆传媒鈥� Chief Anchor and Senior Editor Lisa LaFlamme, security expert Derek Humble said France in particular, has a problem with radicalization.
鈥淚鈥檝e heard that there are huge numbers of suspected jihadists that have been radicalized -- so it is a needle in a haystack,鈥� said Humble, a senior consultant for Globe Risk International. 鈥淵ou could have 鈥� 200 of them, under surveillance and under wraps but then all of a sudden, someone else pops up that they didn鈥檛 look at.鈥�
Though Coulibaly is believed to be an accomplice of the suspects who attacked the Charlie Hebdo office, Humble said it鈥檚 too soon to know whether the kosher market attack in Paris was the result of a true co-ordinated effort.
Humble compared it to the separate terror attacks in Quebec and Ottawa that left two soldiers dead. In both cases, the gunmen were killed.
鈥淐ould they have claimed co-operation if (they) actually survived it?鈥� Humble questioned. 鈥淥r was it just an inspirational move: 鈥楬e did; I鈥檓 going to do it.鈥欌��
Preventing terrorist attacks
Security expert James Carmichael says there are inherent difficulties that limit the ability of authorities to prevent attacks like those in Paris this week.
鈥淜nowing what we know now, it鈥檚 easy to play armchair quarterback,鈥� Carmichael told CTV鈥檚 News Channel Friday. 鈥淭he police operate with their highest risk (with) the current information that they鈥檝e got going on.鈥�
That lack of current information on potential offenders makes the challenge of preventing a terrorist attack that much harder, Carmichael said.
鈥淚f (the suspects) stayed away from cellphones, stayed away from the Internet, stayed in their apartment 鈥� doing this conspiracy to go and assault Charlie Hebdo, it鈥檚 very hard to have information come up on police radar,鈥� Carmichael, a former RCMP officer, said.
To confront terrorism, Humble said, authorities must take a proactive approach, including public awareness campaigns so that civilians know how to report unusual behaviour.
鈥淭his is a dreadful situation, no question, please let's learn from it, Humble said of the Paris attacks. 鈥淟et鈥檚 put some things in place in this country so that the prime minister can stand up and say, hand on heart, 鈥榳e鈥檙e ready for this if it happens, this is what we鈥檙e going to do.鈥欌��
