I Was Jailed at the Beginning, but I Handed over the Evidence of Guilt

Everyone in the martial arts world thinks that I am the most useless prison boss in the border town, the kind that dogs don't even bother to bite. Until the day when the knife was placed on my neck, I handed over a confession - the best swordsman in the world, knelt down. Sorry, before time travel, I was a criminal investigation consultant of the Crime Unit. Can't practice martial arts if all the meridians are cut off? It just so happens that I only care about collecting evidence, setting up situations, and attacking people's hearts. Whoever frames me, I will dig his ancestral grave; whoever kills me to silence him, I will put his whole family on trial.