It struck at the heart of the Iranian regime. After last Friday's daring and sophisticated ambush of 59-year old nuclear physicist Mohsen Fakhrizadeh outside Tehran, the country is mourning him like a national hero. How will Iran respond to yet another assassination of a scientist associated with its covert weapons program? Iran accuses Israel of masterminding the killing. We take a look at the attack itself, and especially the timing of it, occurring in the final weeks of the Trump presidency and ahead of a potential snap election in Israel.