For a day or two, the massive explosion in the Syrian city of Homs was a mystery.

Another Who bombed it? Israeli attack?  Or just more destruction by the Syrian government which already has left Homs a wreck?

Via WaPo on August 1:

What caused this enormous explosion in the Syrian city of Homs?

An unverified video uploaded Thursday by Syrian activists appears to show an explosion many stories high in the war-torn Syrian city of Homs. It’s difficult to tell for sure how high the explosion is, but it dwarfs an apartment complex in the foreground that is at least seven stories.

The footage, embedded just below, captures a fireball fulminating over several long seconds before darkening into a large, mushroom-shaped cloud. A secondary explosion, small only compared to the initial blast, is also visible.

I think we’ve figured it out. From Times of Israel:

Syrian rebels seize arms depot near Damascus

Syrian rebels have captured an arms depot near Damascus Saturday, seizing anti-tank weapons, ground-to-ground Grad missiles, and a variety of other ammunition, said the Britain-based Syrian Observatory for Human Rights quoted by AFP….

On Thursday, rebels sent a wave of rockets slamming into regime strongholds in the central city of Homs on Thursday, triggering a succession of massive explosions in a weapons depot that killed at least 40 people and wounded dozens, an opposition group and residents said.

The attack — one of the most potent against pro-government districts in the area — overshadowed a rare trip by President Bashar Assad to a former opposition bastion outside the capital, Damascus, during which he defiantly vowed in front of troops to defeat the rebels fighting to topple him.

The huge explosion in the Homs district of Wadi Dahab delivered a jolt to Assad’s regime, which for weeks has been boasting of achievements against the rebels in the strategic Homs region and the suburbs of Damascus.

It probably doesn’t change the trajectory of the civil war, though, as Assad and his Hezbollah/Iranian allies continue to make advances, while the rebels turn increasingly to their only source of support, al-Qaeda.

Whatever good once may have been possible in Syria, continues to be just a choice between bad or worse.