Outpost 447 in the main asteroid belt of the Thantor system had suddenly gone dark. No communications of any kind were emitted from it for a three week period. The Thantor System was well behind the frontlines of the Stygian Wars, and the entire system was thought to be under firm Imperial control.
A Passing fast attack craft of the Adeptus Astartes Apocalypse Angels Chapter was passing through system on it's way to the front. A request was made to investigate outpost 447. This request was granted and the fast attack craft arrived and sent down a storm talon to do a quick recon of the outpost. The recon revealed the facility had power still and no damage could be seen on the exterior. However there was no sign of life. A five man tactical squad was dispatched to investigate.
Under the cover of the circling Gunship the squad advanced on the entrance into the outpost. Using override codes the marines entered the facility and began their search. The initial entry showed no signs of confrontation and their armor sensors could detect no virus or toxin in the air. Slowly the marines advanced.
They entered the first large room and saw the writing on the walls along with the blood sprayed crimson across it.
A search of the rest of the facility turned up the bodies of the entire crew that had manned the outpost. Their bodies butchered with obvious savageness. Still the marines could find no trace of the attackers who had put the outpost to the sword. At last they activated the security camera playbacks and the truth was revealed. One of the adepts assigned to the outpost had been a latent psycher who had hidden his affliction from the authorities. over time he had slowly lost his sanity and become corrupt, bargaining with the voices in the warp that only he could hear. At last the voices overwhelmed him and he summoned in a small horde of bloodthirsty daemons that hacked him apart. Then they rampaged through the outpost. Surprise was total and they met little resistance slaughtering all they came across until none were left. Then with no more blood shed to sustain them they vanished back into the warp leaving only butchery behind.
The marines then left the outpost filing their report with the system authorities along with a warning. it was plain on the video they said the consequences that occur when one is less than vigilant in spotting the witch. Suffer not the witch to live the marines stated, or face the fate of outpost 447.