Dandadan, Vol. 16 (manga)

Momo and Okarun task Turbo Granny with uncovering who picked up Okarun's family jewel from the police station. She succeeds in infiltrating the station but is quickly thwarted by the station computers. Undaunted, the pair decide they'll try again, but on their way home, they run into the Serpoian Rokuro, and it's through his powers they're able to identify the culprit! But why is it that guy?