Jiang Yan's father, Jiang Jian, was sent by his father to help the people who were plagued by bandits that were rampant at that time. Naturally, Jiang Jian would have multiple guards to protect him. However, accidents can't be avoided… especially if it might be a plotted one.
When Jiang Yan's father died, his corpse was immediately brought to the palace. Jiang Yan's father died from being tortured by the bandits. When they found his corpse, it was badly mutilated to the point that his bones could even be seen. Even some of the bones that were broken were protruding out of his skin, tearing it. One could just imagine the horrible and painful torture that he had gone through. They didn't dare think further about it.