To learn more about the murder in the taste of her sting in Assassin’s Creed: Origins travel to the Shrine of Serapis. Interact with the corpse on the ground. Go into the cave and interact with the mummy. Interact with the blood on the table. Exit the cave and climb up to the top. Interact with the symbol on the back of the statue. Go back towards the cliff and interact with the scroll on the ground.
As found on Youtube