The anonymous Arab journalist who blogs at The Arab Digest examines those reasons that support the idea that the Assad regime is behind these bombings, versus those reasons suggesting Free Syrian Army or Islamist involvement. In his view, the regime itself is more suspect.

One could say the regime is behind it for the following reasons:

1. Friday is a day off which means more civilians will die than security services.
2. Arab League observers just arrived in town, and such operations serve the regime’s reasoning of current events, and justifies to some extent its heavy handedness.
3. Precedence. The regime has allegedly used a suicide bomber in Lebanon’s Hariri assassination.
4. The FSA has denied its involvement, and accused the regime. The Syrian National Council has previously asked the FSA, and reportedly agreed with its leader Riyadh Al-Assaad, to restrict its role to protecting civilian demonstrators.

But on the other hand, there is the following supporting the anti regime FSA/Islamists involvement:

1. The Free Syrian Army was not happy with the Arab League Observers arriving in Syria. They were counting on the Arab League increasing the international and regional isolation of Syria.
2. The Islamists have a history of attacking the Security apparatuses. These events are reminiscent of the 1980s showdown with the regime.
3. There is growing anger in the conservative cities and regions, against Damascus and Aleppo for not joining the revolution. This might be a warning.
4. The FSA is not an organised force. The Islamists have a different cell-based structure and might go about such operations without consulting anyone. In Iraq, they had no political calculations whatsoever except to ruin any political process, and promote Sectarian violence.

Both are strongly supported. Still, I see the regime blamed for the bombings due to the timing, and for it being the main perpetrator in repression and violence (the stronger side in violence, and the violent one in repressing peaceful demonstrations). Also, the fact that the regime quickly accused Al-Qaeda and had a team of media people quickly reporting and analysing this, will draw more suspicions regarding its possible involvement.