Another update: The landlord left me a phone message last night, asking me (again) not to divulge to the new tenants across the hall from Bruce's apartment the REAL reason that Bruce left all his stuff behind for the landlord to clean out. He told me his "cover story" which I am to corroborate if asked: that Bruce just moved without telling anybody. Since it's really the truth, in a way (he definitely moved on), I have no problem with that! I'm not sure how to explain away the fact that the guy's Jeep is still in the parking lot, though... except to plead ignorance and say "Ask the landlord".
The landlord also said he'd hired professional cleaners to come in next week – biohazard cleaners!!!!! (Makes me wonder if I should mention this whole episode to my doctor!) Meanwhile, Bruce's "stuff" is out back by the dumpster, waiting to be collected, and even in the open air it still smells really bad. Nothing like visual – and olfactory – aids for reminding oneself of a nasty incident!