Playing a prank on CID Sid

My school’s deputy head, Mr Boot, was nicknamed Sid, not because of his name, but because he fancied himself as a detective, solving any school mysteries in the manner of the Criminal Investigation Department, the C.I.D. I played an elaborate practical joke, putting together a package containing an old wallet with a few foreign coins, a photo of a French pen-friend, several letters from firms selling optical equipment, all with the identifying address at the top removed, and a defunct fountain-pen amongst other items. There was nothing that could be identified. I left it on a school window ledge.

The package did the round of the classes, with people asked if they could identify any of the items. The chemistry teacher later told me that Mr Boot had laid all the items on the staff-room table in a bid to ascertain who owned them. Rather cheekily I asked the school caretaker if anyone had found such a package, only to be told that Mr Boot had asked to be told if anyone tried to claim it. I quickly assembled a similar package and took it to the caretaker telling him I had found my missing package. There the story ended, except that when the chemistry teacher laughingly asked if I’d had a hand in it, I shook my head and put on an innocent expression.