Washington, Dec 28: Umar Farouk Abdulmutallab, the Nigerian US plane attacker has been discharged from the hospital and kept in an undisclosed place.
It has been reported that the US investigators are trying it find out the motive behind the Abdulmutallab's attacks on the US plane on Christmas eve.
Abdulmutallab was arrested on for trying to set off explosives aboard Northwest Airlines flight from Amsterdam to Detroit.
He was taken to hospital in Ann Arbor, Michigan to get his burns treated.
According to media reports, Abdulmutallab's father had informed the US embassy in Nigeria about his son becoming a radicalized.
However, a US official said that his father did not have enough evidence to get his visa revoked, adding that canceling his visa would alert him.
"If we pulled his visa or banned him from flying, that would have alerted him you are onto him, whereas in some cases if you have a terror lead, you watch to see what happens when he travels, which could be more valuable, " the official
He said, it was "fairly early in the process of what kind of threat this guy poses."