. >> reporter:22-year-old canadian damon peermont was killed in syria last year after being recruited to join isis. his mother says it could happen to anyone. >> they seemed to colleleively surround that person, enjoy their company, tell them how great they are, how wonderful, give them lots of attention. slowly guide and manipulate their thoughts. >> reporter: she says those who have been radicalized do >> are they cutting off a bit, pulling back, more private, spending more time alone? same idea you'd look for anybody suffering depression, perhaps. >> reporter: in three videos released this week isis vowed similar attacks in america, one threatening th white house will turn black with fire, allah willing. u.s. officials say they have deteteed no specific threats against the u.s. >> the taxpayers of this country have invested a lot of their money in building a national counter terrorism capability since 9/11. and that has built something very strong. we are not perfect but we are good. counterterrorism is what you pay us to do. tell us what you saw and then go on living your lives wh