Mystery Trio Sticker

Seems this detective trio have stumbled upon a clue, but what is it? and who left it there?

Size 3 x 1.6 inches

 Printed on Matte Vinyl Sticker paper and covered with a laminating sheet

Sticker is not waterproof or sunlight resistant. It is only water resistant

Do not place in a dishwasher, and instead hand wash only. If the sticker is ruined

due to not following care instructions is not viable for a refund!

Colors may very slightly depending on your screen settings!