If he was smart, he would not have sent a letter, but sent it in Vacation brochures from a DC travel agency to the mother-in-law or Michelle. That surely would have made it inside. Or an envelope from the NAACP or Rev Wrights church.
If it will save lives, yes. If there is an imminent threat of mass murder, yes. If the person is a true terrorist and part of terrorist organization, yes. Why don't you try kissing him beater? Maybe he will come clean for you.
You did not mention who it is? Someone you know maybe?