One day he'd catch him at it, John vowed, staring into a refrigerator bare of everything but assorted condiments and cheap beer. There had been food in there last night at bedtime, actual, real, not-from-a-packet food, and he was pretty sure that Mrs. Hudson hadn't popped upstairs to nibble his apricots in the middle of the night. It had to be Sherlock I-don't-eat-when-I'm-working Holmes.
Resigned to choking down marmite and stale biscuits for breakfast, and certain that the current nicotine coma would prevent interruptions, John began plotting. Evidence. That's what he needed.
Time to hide a camera in the pickles.