Then answered Doeg the Edomite, who stood by the servants of Saul, and said, I saw the son of Jesse coming to Nob, to Ahimelech the son of Ahitub.
So the one escaped to David from the house of Ahimelech, and David felt really responsible for the death of all of those families. He knew that he made a mistake in letting this Doeg go. He should've killed him. "