Toronto ( CNN ) -- Two men authorities say played a key role in a 2009 al Qaeda plot to bomb packed New York subway cars now face charges in Canada , although their whereabouts are unknown , police said Tuesday . At a news conference in Winnipeg , Canadian police accused Ferid Imam , a former student at the University of Manitoba , of training Najibullah Zazi , the Afghanistan-born New Yorker who has pleaded guilty to trying to bomb the city 's subway system . Imam was identified by the New York plotters as a weapons instructor who went by the name of `` Youseff , '' police said . `` This extensive and thorough national security investigation has provided us with the evidence we require to lay criminal charges , '' said Bill Robinson , assistant commissioner with the Royal Canadian Mounted Police . Imam , 30 , is charged with instructing to carry out terrorist activity and conspiracy to participate in the activity of a terrorist group . Another Canadian , Maiwand Yar , 27 , was charged with conspiracy to participate in activity of a terrorist group and participation in the activity of terrorism . Yar is also a former student at the University of Manitoba . Imam and Yar are now the subjects of an international manhunt that is believed to include the CIA . Canadian authorities said the Canadians left their homes in Manitoba in 2007 , bound for Pakistan , in order to train for and carry out terrorist acts against NATO forces in Afghanistan . Robinson said the investigation is ongoing . `` We continue to work with Canadian border services and domestic and international security partners on this matter , '' he said . Canadian authorities confirm to CNN that their Pakistani counterparts provided help to them during the investigation , but they now have no firm leads on the whereabouts of the two men . `` Are they still alive ? There 's been no proof of life for more than a year , '' Gilles Michaud , the RCMP 's assistant commissioner , told CNN . Police believe the suspects were in the tribal areas of Pakistan about a year ago , but have had no credible intelligence about their whereabouts since then . Canadian counterterrorism and government officials say the radicalization of these men , and others from North America and Europe represents a true reflection of a small but dedicated group of recruits that pose a direct threat to national security . `` There is no set criteria . It affects all walks of life . These were well-educated , young individuals with no past criminal history and supportive families , '' Michaud said . U.S. authorities charged Imam in July with providing material support and receiving military-type training from al Qaeda , according to an indictment unsealed Tuesday in the Eastern District of New York . Federal prosecutors allege that Imam , while in Pakistan in 2008 , helped train Zazi and Zarein Ahmedzay advance of their plot to detonate bombs on subway trains on the eighth anniversary of the September 11 attacks , according to the indictment . Imam is also charged with use of a destructive device , the indictment said .
NEW : Canadian police have no firm information on the suspects ' whereabouts . The two men are accused of role in al Qaeda plot . They are said to have departed for Pakistan in 2006 . Police say their current whereabouts are unknown .