Let's be straight, here: we're all of us a little bent. Crime writers. Mystery fans. Creepy blog-lurkers. (Oh, I don't mean you; you're lovely, I'm sure. It's those other pantsless, lurking weirdos I'm talking about.) To a one, we spend way too much time contemplating acts of moral turpitude.
We like to fancy ourselves closet Marples and Poirots, who could at a moment's notice employ our dazzling skills of deduction to nab the bad guy and save the day (though truth be told, the mysteries we're called upon to solve are often of the Who took my lunch from the break room? variety, and only rarely involve gunplay.) But let's face it, we require naught but the gentlest nudge (a near miss in traffic thanks to some texting idiot, that crapweasel on Amazon who called my debut novel "dreadful," a particularly tempting set of someone else's leftovers in the break room) to find ourselves on the other side of the law, if only in the wild hypotheticals of our own minds.
But when it comes to such wild hypotheticals, I confess I tend more toward the break-room-lunch-heist than I do murder. If I'm going to step across the good guy/bad guy divide, even in the dark recesses of my most private thoughts, it'll be to boost a Rembrandt or knock over a casino, not to pop someone who wronged me.
That's not to say I haven't considered whether there's any such thing as a perfect murder. I've spent as much time pondering the topic as any crime writer. Some folks think they're imaginative enough to pull it off. I'm imaginative enough to convince myself that, statistically at least, it's un-pull-off-able.
The key to getting away with murder isn't, despite what most people think, in the (brace yourself for painful pun) execution. Folks kicking the tires of the Hypothetical Perfect Murder spend a lot of time pondering, for example, how to make sure the body is never found and/or unidentifiable. But here's the thing: in this day and age, it doesn't matter. There are simply too many variables to properly account for all of them. A weighted deep-water body dump sounds quite clever, and it was mighty shrewd of you to remove the head and hands for disposal elsewhere, but it won't do you a lick of good when your well-known grudge against the nefarious Lunch Taker comes to light, and the cops track your movements using the literally dozens of security cameras you pass by every day, only to find trace blood evidence on your neighbor's outrigger. And I don't care if it was your granddad's favorite hacksaw: you should've chucked it. Plus, let's face it, you're no hardened criminal; once they get you in the interrogation room, you're gonna fold like a cot.
No, the key to getting away with murder is in the target selection. Cops rely upon means, motive, and opportunity. Serial killers tend to sneak below the radar for a while because until their pattern becomes known, they often lack motive, and their faulty mental wiring means they're ready to kill at a moment's notice. So if you want to get away with (again, strictly hypothetical) murder, you'd have to bump along in life with your bloodlust set to a constant simmer, but never allow it to boil over until the perfect, utterly random opportunity presented itself (e.g. a complete stranger with whom you've never interacted, no witnesses or cameras, a method both quick and unlikely to leave forensic evidence). That means you don't get to exact your revenge all Dexter-style on the jerkface who ate your lunch, so much as nudge a poor drunk hobo off an empty wharf at 3AM, only to wonder in the weeks that follow whether you were correct in your assessment that you were not seen. More sad than viscerally satisfying, no?
And here's the final key to getting away with murder: once that perfect, lightning-strike opportunity presents itself and you take action, you can never, ever kill again. Which sounds like an easy rule for a normal person to follow, only if the scenario I just outlined appealed to you in the slightest, you're probably psychotic, and therefore unlikely to go all one-and-done in the murder department. Which means a nice, long stay at the ol' Graybar Hotel is almost certainly in your future. Patterns can be predicted, after all, and whether you think you have one or not, Hopefully Imaginary Psychotic Reader, I assure you, you do.
I'm not saying folks never get away with murder. Obviously, some do. But it's often more luck than planning, with a healthy heap of underlying depravity on the side. And the vast majority of murderers are caught, thank God. Sometimes it's the evidence that gets 'em. Sometimes, it's their consciences. Raymond Chandler once referred to murder as a "simple art," but to steal a line from one of my own stories (about, as it happens, a killer with a conscience), "Mind you, simple's not the same as easy."