Thanks to Thoronir’s tip, you can travel to the Trentius Family Mausoleum in the Imperial City. Inside, you find Agarmir and a guard messing with a grave. Agarmir confronts you and explains that he laid this trap for you, and challenges you to a fight. You need to take out both Agarmir and the guard, which can be difficult, as Agarmir is wielding a sword called the Debaser, which drains your willpower and endurance on hits.

Once Agarmir and the guard are dead, loot their bodies, and then have a search around the mausoleum. You need to find an item that proves Agarmir’s guilt in this scheme. If you travel to the back of the room, find the central coffin, and just to the left of it, you can pick up Agarmir’s Shovel. This is all you need to prove his guilt.

However, before you leave, you can also check Calliben Trentius’ coffin, which is on the left side of the room. Just behind the stone statue inside the coffin is a weapon called Calliben’s Grim Retort, which is quite a powerful mace in Oblivion Remastered. If you played your cards right, you’re walking out with two strong weapons.