Miami , Florida ( CNN ) -- He was born in Saudi Arabia and spent much of his youth in New York and south Florida . Then he vanished . Investigators now allege that Adnan Shukrijumah has risen to a key position in al Qaeda 's leadership . The FBI says that after he left America , Shukrijumah started off as an al Qaeda dishwasher , doing menial tasks at training camps . But he 's much more than a dishwasher now , according to investigators . `` It 's like any other business . He would be equated with being the chief of operations , '' says Brian LeBlanc , a special agent for the FBI . As the alleged director of al Qaeda 's overseas operations , investigators believe he is `` extremely dangerous , '' LeBlanc says . `` He may not be someone who 's going to come into the United States to conduct the attack , but what makes him more dangerous is he 's out there plotting the attacks and recruiting people to actively do that , '' LeBlanc says . The breakthrough came when LeBlanc , an FBI counter-terrorism agent , linked Shukrijumah to the thwarted New York subway suicide mission last fall -- the biggest post-9/11 terror investigation . Najibullah Zazi and Zarein Ahmedzay admitted they planned to blow themselves up using homemade bombs . Prosecutors say it was Shukrijumah who called the shots -- probably from somewhere along the Afghan-Pakistan border . `` [ Shukrijumah ] was the one that convinced ... them to come back to the United States and conduct the attack here , '' LeBlanc says . But Shukrijumah 's mother -- who did not wish to be named in order to protect her privacy -- says authorities are using her son as a scapegoat . `` That is not my son . My son is not a violent person . He is very kind , generous , '' she says . Shukrijumah -- the eldest son of a Saudi Imam -- came to America as a young child . They settled in Brooklyn , New York , where his father preached at a mosque . They lived at a nearby house before moving to Florida in the mid-'90s . His father , who is now dead , opened a small mosque near Fort Lauderdale . Meanwhile , Shukrijumah worked at odd jobs , including selling used cars . His family says it 's how he paid for courses , including computers and chemistry , at a small college in South Florida . He even took classes to improve his English . A few years later , when the FBI said they wanted to find him , Shukrijumah 's English professor remembered videotaping him in class and turned over the tape to the FBI . That proved crucial six years later . On a hunch , LeBlanc asked agents in New York to show that video of Shukrijumah to would-be bomber Zazi . `` From that video , he was able to make an identification , '' LeBlanc says . The FBI says it now has a more detailed profile of Shukrijumah in part , from 9/11 mastermind Khalid Sheik Mohammed . Just before 9/11 , the FBI says Shukrijumah crossed the U.S. by train . Later , he scoped out the Panama Canal as a target . He went to Trinidad , London and -- by June 2001 -- Afghanistan . On 9/11 , his mother says he called home for the last time . `` He called me and he said , 'Did you hear what happened with so and so and so ? ' He said , 'They 're putting it on the Muslims . I said , 'yes . ' '' She says she told him not to come home . `` And he was arguing with me . He said , 'No , I did n't do nothing . I will come , do n't worry about this , ' '' she recalls . After that , she says , she never heard from him again . Shukrijumah 's mother adamantly denies her son is directing al Qaeda attacks . But when asked about Faisal Shahzad -- who has pleaded guilty to federal terrorism charges in the attempted car bomb attack in Times Square in May -- she says that sometimes `` you have to do something very alarming for the people to wake up . '' `` It 's not because you hate them or you want to destroy them or you want to hurt them , '' she says . When asked if she has a message to send her son , she says she has nothing to say . `` He [ has ] his own guide in his own heart , '' she says . For the FBI , it 's all about staying one step ahead . Where will al Qaeda -- and their alleged chief of operations -- strike next ? `` He 's definitely focused on attacking the United States and other western countries , '' LeBlanc says . The FBI believes Shukrijumah is likely in Pakistan 's lawless tribal region of Waziristan . Shukrijumah moved up the ladder after two others who directed outside operations for al Qaeda were killed in suspected U.S. drone attacks , the FBI says .
FBI says Adnan Shukrijumah started out as a dishwasher and worked his way up . Investigators allege he is the director of al Qaeda 's overseas operations . FBI agent calls him `` extremely dangerous '' His mother says he is not a violent person and authorities are using him as a scapegoat .