I enjoy watching the History International channel on TV. They have a program called "Ancients Behaving Badly". The other night they focused on Julius Caesar.
When he was a young, up-and-coming politician, he was captured by pirates and held for ransom. The pirates were going to ask for 20 silver talents (the narrator said that would be around $130K in today's money). Caesar laughed at them and told them that he was worth 50 talents. They adjusted their demand upward and Rome paid the freight. When he was released from captivity, Caesar told the pirates that he would return and kill them.
When he got back to Rome, Caesar raised a naval force and went out looking for the pirates. He found them, defeated them and, true to his word, had them all crucified. However, being the reasonable person that he was, because they did not harm him during his captivity, he mercifully had their throats cut after they had hung on the crosses for awhile.
That's how you do business with terrorists.
If you play cool, you are cool.