Doeg slays priests in the town of Nob. Image from Mud Preacher.
This guy Doeg doesn't mess around. Apparently, he was the chief servant of Saul, and very loyal. After hearing that David had fled to the town of Nob, Saul and his servants traveled to the little town. Saul gets into a minor dispute with a priest named Ahimelech, and afterward asks his servants to slay the priests. None of them moved.
So Saul turned to loyal Doeg and asks him to kill the priests. Without question, Doeg turned on his heals and commenced slayed 85 priests. He even killed multiple men, women, and children of the town too!
The only person who managed to escape was the son of Ahimelech, Abiathar, who fled and found David, reporting all he had seen. David felt bad for Abiathar. David actually felt partially to blame for the death of all Abiathar's family.
David told Abiathar not to worry or be scared, because he is safe with him.