fart detective
Someone Farts and no one admits to it so they get the fart detective on the case to find out who did it.
True story, last friday I was on the bus to work and someone let rip. Damn it smelled! People started to wretch. A lilttle old lady became a fart detective and searched out the culprit who turned out to John Connor after a curry.
fart-detecting compound
A.k.a. finely-pulverized talc. A substance utilized when you want to find out who's been cutting the cheese, but nobody's willing to 'fess up; the simple procedure involves having everyone strip down and stretch out on their stomachs, whereupon you sprinkle a moderate dusting of baby-powder on the lower half of their ass-cheeks, then watch for a "puffball eruption" --- busted!
Using fart-detecting compound can indeed be an excellent way of reliably determining "who did it", but you will want to be wary about slapping said odiferous-offender's butt afterwards, especially if you're an attractive female --- as you are all too aware, many dudes actually **enjoy** getting spanked by a cute gal (we find it fun and hilariously amusing, plus it makes us horny), and so your hot-headed attempt at getting back at said "whistleblower" may actually "backfire" --- literally! (Pun not intended, but certainly spot-on appropriate in this instance!) Said gassy dude --- and by extension, one or more of his other buddies in the room --- may then begin actively "tuning up the brass band" (and possibly even chow down on baked beans or other gas-producing delicacies to ensure an ample/continuous "supply" ) so as to "earn" smartly-administered swats from you, eventually leaving you with stinging palms and a major headache from da resulting stench.