The great oil mystery!

I work with about 20 other people in a small office in a seven story building.  The other day we got a very terse email from building management.  It stated that there have been several reports of people finding oil in the toilets from the janitor.  It also made clear that this behavior would not be tolerated.
I read it a few times put my head outside my cubicle to see who was pulling the prank and then laughed.  Hard.  My laughter drew a few office mates over and we were all cracking up.  I postulated that a person came in with baggies of oil from their deep fat fryer and dumped them in the toilets during various times of the day.  OK I know that is far fetched but I mean how else is oil getting in the toilets.  I had all sorts of visions about it and the tense janitor who wanted to bring CSI to the building and find the culprit.

I did see that a ceiling tile was moved and thought maybe they were filming but they just changed the the lamp in the light fixture.  As the day went by we did our work and giggled about who on our floor was the oily bathroom bandit.  Then a gal at work said she was pretty sure what it was....

So tell me!  I have to know. There is no logical answer.  Her response. Diet pills.  Her face drained of color.  This is when I had to start pinching myself to keep from cracking a smile.  What the what now?  Diet pills they make you defecate all the fats and oils you ate.  (pinch pinch pinch)  Sometimes it can even cause anal leakage.  (pinch pinch pinch pinch)  This is when I said, "huh that is so interesting" .  She went to have a meeting with the boss and we received no more emails about the oily crappers.  

The bravery it must have taken to reveal that someone was an oily pooper is amazing.  My ability to keep a straight face is magical.

Moral of the story:  If your taking diet pills that make you defacate oil and the building tries to track you down: Deny Deny Deny.  How would they prove that and last I checked pooping oil is not against the law anyway.