I, Krolbrim, am writing this report for your records, compiled both from what I personally saw and from statements taken from those who saw what I did not. I hope my doing this can take some of the burden from you, particularly after what happened today.
We received a request for aid from the Horde forces at Sun Rock Retreat, in the Stonetalon Mountains. Upon arrival, we met with a Grunt, going by the name Thoruk Deathhowl. He informed us that a group of undocumented Horde troops had passed by recently, toward the Ruins of Eldre'thar. The Horde believed that these were demons in disguise, planning to harness the power of the ruins.
We moved south, and were ambushed by these "demons". One of them was a sniper, perched atop a nearby tower. One of the Undead, Swerto, fired a plague grenade at him. This resulted in his death, when he fell from the tower.
While I know you understand this, I want to emphasize the evil of this action. Swerto had been told to fight nonlethally, but he nonetheless used a weapon that could only possibly be lethal. Furthermore, he used a weapon that could have significant fallout on the local area. I've already informed the Cenarion Circle, who will see to minimizing the damage.
However, if the Scythe of Sylvanas cannot keep their dogs leashed, I cannot help but wonder if maintaining this alliance is really worthwhile. I won't press you to make any kind of decision - I would not be in this group if I did not trust your judgment. But I believe this incident makes it clear what caliber of people tend to be found among their number, and that we need to consider carefully before associating ourselves with them.
Back on subject: The 'demons' surrendered to us after a short skirmish, during which this sniper was the only fatality. They told us that they were told demons would be coming to seize control of the ruins, and so they set an ambush. I remained behind to patch them up, while the rest of the group returned to the Retreat to demand answers from Thoruk.
During my time with the group, I learned they were a small mercenary company, not dissimilar to our own, though much smaller in scale. Once I finished healing them, they returned to Orgrimmar to lick their wounds and arrange a service for their comrade; I gave them your contact information so that they can contact you if they need anything for the service, as you said. I don't expect they'll be in touch, though; their leader seemed to be taking responsibility heavily on himself.
As for the rest of you, upon arrival back at the Retreat, you found that Thoruk had apparently left shortly before your arrival. You demanded his location from the sergeant who was placed in command of the small garrison at the Retreat, due to its usual leadership being temporarily displaced by the military response to the Legion's activities.
He refused to assist you, and there was almost an altercation. Before there could be, a Demon Hunter descended and revealed the sergeant for the demon he was, and slew him. She informed you that Thoruk was, in fact, a demon - and that she'd let him escape to leave a trail back to the Legion's base of operations in the mountains.
Agreeing to work with her and the other Illidari, she vowed to lead the group right to the demons once she's had time to do so.
For the time being, we wait for contact from the Illidari. When the time comes, "Thoruk" will pay for his crimes.