On Friday, we asked three questions about the dramatic attack on a regime arms depot in Homs:

1. What was targeted?
2. What weapons were used?
3. How many people died?

We still do not have definitive answers. Instead, we have more questions.

Who carried out the attack?

Soon after the explosion, Liwa al-Haq said that it fired the rockets, according to analyst Charles Lister.

Not much has been written about Liwa al-Haq. The brigade is part of the Syrian Islamic Front, a coalition of about 12 groups announced in December — its best-known member is Ahrar al-Sham, which may have the largest force in the insurgency. The SIF in turn is linked with the Free Syrian Army.

However, apart from Lister’s references to Liwa al-Haq, there has been no other testimony about responsibility. There has been no further declaration from the brigade, and neither the Syrian Islamic Front nor the Free Syrian Army has made any statement.

I asked a valued EA correspondent to check with contacts inside Syria and make an assessment. His response:

Besides Liwa al-Haq, other brigades were involved. It was a second try — an earlier operation to attack the base failed. They fired small rocket(s) to hit their targets precisely.

It was a long-planned operation targeting the regime’s capabilities to shell the city.

Given the regime’s offensive since early June to reclaim all of Homs — which succeeded in capturing Khalidiya earlier this week — that assessment makes sense.

However, because of the vacuum of information, another rumor has sprung up, with a leading activist pushing it on Twitter:

At this point, the claim appears far-fetched. Even if the arms depot was storing missiles that were en route to Hezbollah — the target of previous, night-time Israeli attacks inside Syria, and probably the only reason why Israel would strike — this would have had to be a high-risk, daylight air raid requiring days of pre-planning. There have been no reports of a warplane spotted in the area just before the explosion

A variant of the claim is that Israel co-ordinated its attack with that of the insurgents, or at least found out the timing of the insurgent attack so it could follow up with a bigger assault minutes later.

This is implausible, at best: the theory assumes either that Israel is working closely, with its forces on the ground, with insurgent factions — including those who are quite hostile to the Israelis — or that the Israeli intelligence services have infiltrated deep within the Syrian insurgency.

Such speculation has not only diverted from the quest for a more realistic — and needed — evaluation of who attacked the Homs arms depot — it has obscured other questions.

For example — amid recent tensions over the provision of arms to insurgency by foreign actors, with claims that US reluctance has crippled the opposition’s efforts — who supplied the high-precision rockets used on Thursday?