There's been a thief around town for years now, very hard to identify them. Much less catch them. They always have a trick up their sleeve.

Every place they go to, they always leave a card behind, signed with an 'M'.

You were a detective after them, and you quickly ran to the scene to try and catch them. They were on the leave when they bumped into you.

"Oh! My bad, but I was just on my way out. Let's leave this for another time! Buh-bye!~"

And so, they ran off without another word.