A week ago today, a group of armed men went methodically about their business, in and around the town of Houla, north of the Syrian city of Homs.
Their business was killing -- slaughtering, if you prefer, or massacring.
By the time they'd finished, more than 100 people were dead, several dozen of them women and children, most of them stabbed to death or shot at close range.
This is not the unsubstantiated claim of opposition activists whose credibility may be suspect. This is the account of United Nations observers, who were on the scene shortly after the attack, collecting eye-witness accounts and collating evidence.
So who were these armed men, the "shabiha" (ghosts) who are blamed so often for the most appalling crimes committed in Syria?
The government calls them "armed groups", and says they are armed and financed by foreign powers. (It means principally Saudi Arabia and Qatar.)
The opposition say they are pro-government militias, recruited by the regime of President Bashar al-Assad to do the dirty work that the regular military either can't, or won't, do themselves.
Alex Thomson of Channel 4 News has been in Houla since last weekend and has filed a remarkable series of reports throughout the week. Yesterday, based on extensive interviews with local people, he wrote this account of what he believes happened last Friday:
"There was an extensive Syrian Army shelling barrage, then around one hundred men were able to enter the shelling zone without a single mortar, bullet or shell landing anywhere near them from the Syrian Army side. Perhaps that is simply coincidence. Perhaps it indicates clear communication and co-ordination between the two groups.
"With no firm proof either way forthcoming as yet and possibly not ever, you have to believe in either staggering luck and coincidence, or prima facie evidence of co-ordination and planning."
So, in the words of Foreign Policy magazine this week: "What the hell should we do about Syria?"
On the Today programme this morning, the foreign secretary William Hague insisted that the priority remains to find some way to make the six-point peace plan drawn up by the international envoy Kofi Annan work. That seems to be closer to forlorn hope than realistic policy.
So here are five alternative policy options, as collected by Foreign Policy from various US-based Syria analysts, which I summarise here for your benefit:
Robin Yassin-Kassab, author of The Road from Damascus: "The damage is already done. It's already too late for a happy ending. The civil war is here, and the longer the stalemate lasts the deeper the trauma will be. This is why I support supplying weapons to the Free Syrian Army. Let's get it over with as soon as possible."
Rand Slim, of the New America Foundation and Middle East Institute: "Time and again, Iranian senior officials have stressed the need for a political resolution to the Syrian crisis. They have been reaching out to different groups in the Syrian opposition. As the Western community keeps searching for a political solution in Syria, Iran might have some ideas about how to bring it about."
Bilal Saab, of the Monterey Institute of International Studies: "Kofi Annan's U.N.-backed plan has served its goal of exposing the Syrian regime before the world. But that was all anyone could realistically hope … It's time for real and serious negotiations with Russia over not just Syria but a range of Middle Eastern issues of concern to both countries. But the Yemenskii Variant [ie a plan similar to the one which levered President Saleh of Yemen from office] is not it."
Andrew J. Tabler, of The Washington Institute for Near East Policy: "As Syria's conflict tragically unfolds, Washington may need to carry out surgical airstrikes or similar measures to stop regime forces from attacking civilians. If those strikes are to succeed in toppling the regime, however, Washington and its allies will need to have cultivated an alternative leadership from the fragmented Syrian opposition. Conflict will be the constant in Syria for the foreseeable future. But conflict does not necessarily have to set off a generalized civil war -- the opposition on the ground has come together over one issue: Assad must go at all costs. The question is how to get there."
Andrew Exum, of the Center for a New American Security: "As the United States works to facilitate a transition, it must also recognize the limitations of its leverage over Syrian actors, prepare for the likelihood of a long conflict in Syria, and work to mitigate the effects of that war on U.S. interests. This means containing the conflict and discouraging human rights abuses while seeking a political solution."
I shall be taking a few days off next week, so the next newsletter will be in two weeks' time, on 15 June.