It is, literally, a bomb. What kind of wily actor managed to get the precious intel needed to penetrate, disrupt and destroy a meeting at the National Security building in Damascus -- killing Defense Minister Dawoud Rajha and his deputy Assef Shawkat, Bashar al-Assad's brother-in-law?
So who was it? The Central Intelligence Agency (CIA)? The MI6? Saudi intel? Turkish intel? Or that oh so pliable ghost -- al-Qaeda?
US Secretary of State Hillary Clinton, five months ago, came up with a non-denial denial by in fact admitting that Washington was working side-by-side with al-Qaeda in Syria supporting the Not Exactly Free Syrian Army (FSA). 
The FSA -- out of its Turkey digs - - wasted no time in claiming responsibility; it was an improvised explosive device (IED) planted inside the room. There were no suicide bombers. Yet the FSA have been lying through their teeth for months. Anyway, FSA spokesman Qassim Saadedine insists this is "the volcano" they promised to awaken a few days ago.
Much juicier, in parallel, is the Liwa al-Islam ("The Brigade of Islam") saying in its Facebook page that it "targeted the cell called the crisis control room in the capital of Damascus." That would be the al-Qaeda-style connection. In this case, where are they getting their intel from? Their good pals, the CIA?
Time to round up those canolis
The Assad family saga does read like a ready-made script for Godfather IV, as evoked in this collective foreign-policy blog discussion before the bombing.
Assad's brother-in-law, General Assef Shawkat, was a big security honcho -- widely viewed as the actual ruler of Damascus. He was born out of a poor Bedouin family who settled in Tartus -- where Russia keeps its naval base. Shawkat was the leader of a special brigade during the 1982 Hama massacre -- whose victims were essentially from the Syrian Muslim Brotherhood (MB).
Then Godfather Hafez al-Assad put him in charge of protecting his daughter Bouchra. They sort of fell in love with each other. Bouchra's brother, the unruly Bassel al-Assad, was violently against it; he had Shawkat, whom he dismissed as a country bumpkin, arrested at least four times. Bassel died in 1994 in a car accident; conspiracy theorists blamed it on Rifaat al-Assad, Hafez's brother, who lived in France and who badly wanted to be Hafez's successor.
Bouchra and Shawkat had to flee to Rome to make the Assad family face the inevitable. Patriarch Hafez ended up giving them his blessing, and they finally got married. Hafez then put Shawkat in charge of preparing Bashar to become president. From 1998 onwards they got really close; that's how Shawkat became the most powerful man in Syria. Inevitably another blood feud crept up -- this time with Maher, Bashar's younger brother, the commander of the 4th Division, who even shot Shawkat; he had to recover in a hospital in Paris.
WikiLeaks cables have shown how Shawkat was very close to the French security establishment. They've also shown that Shawkat was in charge of everything related to US-Syria security exchanges. So Shawkat was not exactly a persona non grata in Washington; he was "one of our bastards" as well.
The key point is that since becoming president in 2000, Bashar has always relied on Shawkat. He was Bashar's Richelieu - even though he had no popular base, nor even full support among the Alawite elite.