The story is at http://heritage-key.com/blogs/owenjarus/did-uruk-soldiers-kill-their-own-people-5500/ so a certain element of scepticism might be advisable. Anyway, the story proceeds with excavations at a city in Syria, Tell Hamoukar, and a destruction layer that is provisionally dated to 3500BC (but within the window of 3500-3000BC or the end of the Mid Holocene Warm Period). It is assumed by archaeologists the city was captured and burnt by hostile forces and the defenders used sling and clay pellets as many of these were found near the walls of the city. We may note whatever caused the destruction, natural disaster or human, those clay pellets would have been located near the walls for strategic reasons so this is proof but it is not conclusive. The motive for the attack is assumed to be control of a lucrative trade in obsidian and copper from southern Anatolia, and the likeliest agressor, it was concluded, was Uruk, the most powerful – rather, the largest city state in Sumeria to the south. This deduction, it is said, is supported by the discovery of artifacts in Hamoukar that are similar to those found in Uruk, proof of such a connection. However, it is then suggested Uruk took over Hamoukar after capturing it – as Sumerian links continued. Now, to compound things, archaeologists have actually found a trade colony from Uruk near Hamoukar that was also destroyed. Archaeologists, dead set on human destruction as an explanation are now asking, why did they kill their own people?
Hamoukar was a thriving city as early as 4500BC and was contemporary with the expansion and commercial web of Uruk throughout that time – and various other city states not mentioned, both in Syria and in Sumeria, even in the Jordan valley and the highland zone of northern Mesopotamia. Hamoukar’s prosperity was based on obsidian and copper and the trade colony of Uruk was presumably there as intermediaries in trade. All quite simple in the economics of the era. However, it is the speculation on the destruction layer that makes one wonder as it is seriously alleged that soldiers from Uruk were responsible for the destruction not only of Hamoukar but of the trade colony as well. One idea is they may not have been aware they were attacking their own people (bodies were found) which appears somewhat strained to say the least. Another idea is that the trade colony was in league with Hamoukar in some kind of conflict of interests, or the king of Uruk was a complete meglomaniac. Seriously, it is being suggested the inhabitants of the trade colony were traitors of some kind in order to maintain the unlikely explanation of human conquest. This kind of unneccessary double-think is annoying, mostly because archaeologists are obsessed with avoiding natural disasters such as earthquakes, and because they are blinkered at looking at the single site instead of at what was going on around Hamoukar. The wider picture is revealing as many sites in Syria and SW Asia in general were destroyed in the same window towards the end of the fourth millennium BC – including Uruk.