Considering evidence gathered by interrogation of the corpses that were discovered in the stables, I am forced to consider that the dopplegangers did not kill the Black Sword adventuring company. The slain Black Sword member clearly stated that he was killed by a grey skinned humanoid, and it is very unlikely that it would be a doppleganger as they would not risk or bother with assuming their natural state in order to murder someone, especially when they were using such things a large swords, and then they only would take their form on death, and since they were stated to be the killer not just merely in the combat it does not make sence that the corpse could be referring to a doppleganger. Even if that was the case the natural form of the the doppleganger is a pale skin not grey skin, so I believe that the doppleganger hypothosis can be ruled out.
My second hypothesis, which Donnathan shared with me and the rest of the group was that Svirfneblin, the deep gnomes, whose skin is grey, were behind the attack. This would mean that for some reason a typically neutral race of underdark dwelling creatures had somehow infiltrated our city in order to kill a number of people who were dressed up as the leaders of our country, perhaps as agents of some other force or as a peace bribe to the drow who have been pressing into their territory. The drow aggressiveness would make sense considering our past history with the drow but it seems convoluted to collect a group of svirfneblin to do their dirty work considering how capable they are as assassins. I have rejected this hypothesis on further though however, as the weapon marks were clearly made by large chopping sword attacks, and such weapons are ill favored amoung the underground wee folks such as the svirfneblin who favor the use of picks and small thrusting weapons that are better suited for combat in the confines of the tunnels of the underdark.
I have racked my mind thinking of other grey skinned humanoid only to find a long list of creatures that could not logically be thought to be behind this attack. Stone giants are too big they would be noticed. Duegar favor their poisonous spines, axes and hammers. I find it unlikely that the person would have confused a stone golem for a "grey skinned humanoid; nor do I think that a ghost could have left such realistic cuts as their weapons strike the soul of their target not the flesh. The Galeb Duhr fit the description but rarely carry weapons. None of the Undead that fit the description would carry swords as they prefer to tear the victim apart with their claws and teeth, as do Chokers, who are frequently grey colored to blend in with their surroundings. Grimlocks, another underdark denizen favor the ax, instead of the sword. Quicklings once again favor a smaller blade due to their reduced stature. I doubt either the gith or the cyclopi could be as subtle as to sneak into town and kill only a selected group and leave.
This leaves me with only four possibilities. One, there could be a group of grey scaled dragonborn, they would draw less attention to themselves and be likely registered as an adventuring company, however it is my understanding that dragonborn are rare to find in these parts, so to find an entire group that shares the same coloration would be unlikely. Two, it could be a group of lycanthropes whose animal forms have a grey hair such as the wolf does. Three. it could be gnolls, as we are already aware of a gnoll presence in town and while uncommon gnolls can be grey furred. Finally, four, and the worst for us, it could be the Shadar-Kai The grey warriors from the shadowdark who normally use chains and greatswords. If they are getting involved in our city and in assassination here then we could be in great danger. However I feel that because of the way that the bodies had been picked up by a cart and hidden in a stable it is less likely the Shadar-Kai and more likely either Gnolls, or Lycanthropes.
I submit this message to Aeron Mindreaver, Hadarai Kithbane,Sir Marren, (the leader of the war wizards enclave in tilverton), Cliff, Donnathan, and the message is to be read aloud to DuhDum so that he can gain the most benefit from it that he can.
I would like to add to my previous insights that there could be a cult of earth element worshipers who choose to color themselves grey (possibly with a chalk powder) before they go out and cause their mischief. This would allow it to be any kind of humanoid as the coloration would not be natural and therefore it would no longer be a relevant clue in determining who the attackers are.