sources, here's what happened next. as the plane is boarding, agents are moving in. the decision is to allow the plane to shut its doors. before the plane can push back, sources tell cnn, the door is reopened, faisal shahzad is placed under arrest and removed from the flight before it ever leaves the gate. under intense questioning, there's another emergency. two more names onboard the emirates flight appear suspicious. under an abundance of caution, we're told, the plane already taxiing is told to go back to the gate. >> i have a message for you to come back to the gate immediately. >> reporter: two individuals were removed, questioned and let go. the only arrest is faisal shahzad he is said to be cooperating with the investigation and detailing his crimes and travel. >> so drew, he's apparently talking about training in pack staj. do authorities believe him? >> cops don't believe anybody, anderson. they make you prove it, especially, i'm told, in these terrorists case, because these guys really do like to brag, even when they blow it like this guy did.