The drugs trade seems too volatile for my taste.
I've noticed there's a factory that specializes in fasteners in each major Australian city, some of them are called "The Nut & Bolt Shop" but I think they're all owned by United Fasteners based in Sydney. Were I criminally minded I'd conspire to have all the store managers and some of the upper management expire under unfortunate circumstances all within a six month period, y'know car crashes, dog attacks, snake bites, boat sank on a fishing trip, shit happens.
And oh look at that I just so happened to have stockpiled fasteners to meet the sudden shortage of supply, how fortuitous for me, and how forward thinking of me to be setting up a factory with machining equipment just as Australia's leading supplier of fasteners went out of business, such a coincidence.
Good thing probable cause isn't enough for a conviction eh?
It's not like I killed them, they mostly died by accident and I was in a different country at the time, maybe I hired contractors to do the deed for me but good luck proving it.