This is probably not the right blog to ask, but I'm not sure where else: is there a way to write a convincing hitman? Any obvious do's or don't's?
Well, first off it's important to remember that most of the assassins you're familiar with from pop culture are pure fantasy. There's no real world analog for characters like John Wick, Leon (The Professional), Vincent (Collateral), or 47. They belong to a theoretical tier of professional assassins that (probably) don't exist.
I'm going off a 2014 article from The Howard Journal of Crime and Justice, but unfortunately, it's been pay walled sometime in the last 8 years, so this is going to be mostly from memory. The authors classify assassins into four groups: Novices, Dilettantes, Journeymen, and Masters.
Novices are the amateur assassins and hitmen. These aren't really killers for hire, so much as just people who like the idea of getting paid for killing someone. When novice hitmen have ties to local criminal enterprises, it's really easy for police to identify them, because they generally don't travel to commit their crimes. Everyone in the (criminal) community, usually has a pretty good idea who the killer was, and no real interest in protecting them.
Novices who manage to pull off a couple contracts without getting caught graduate into Dilettantes. Again, not a lot to say here, these guys come from a mix of backgrounds. They're not really professionals, but they do commit the occasional killing for pay.
Journeymen are professionals. They may be ex-military, or they may simply be career criminals. As with Novices and Dilettantes, they're likely to stay close to home, which, in turn, makes them relatively easy to identify during criminal investigations. When you're looking at organized crime hitmen, they're likely to fall into one of these three categories. Street level soldiers who get tapped to carry out a killing are usually novices or dilettantes, a criminal enterprise might have some journeymen further up in the organization, at their disposal.
Masters might not exist. These guys have military, intelligence, or specialized backgrounds, they travel some distance to kill their targets, and then they disappear and head home. Here's the problem. All realistic investigation of professional assassins is based examining the failures (something, mentioned in the referenced article.) This means, if someone doesn't screw up, avoids detection, and escapes capture, we don't know anything about them. We only know about the assassins that are stopped or caught. So, let's look at those four fictional characters for a moment.
Wick is a pure fantasy character. He exists in a world with a massive conspiracy concealing a secret society of assassins, that are so well entrenched they mint their own currency. Keanu Reeves is worth watching (in the first film) for his movements, dude moves like someone with a serious combat background. The actual assassin component of the story is just thin connective tissue to tie one fight scene to the next. It's visual art and absolutely worth watching, but not because the writing makes sense.
Leon (Jean Reno, The Professional), is in the range of a journeyman. He operates exclusively in New York, and while it's not (completely) clear how he came to become a hitman, he illustrates some of the problems associated with staying in a specific geographic area. At the same time, not a terribly realistic character, and the idea that the more advanced you, the closer you get to your target is just goofy. It makes for some excellent film, but, if your job is to kill someone, you're not getting paid more to garrote them, than to put a round of .308 through their skull from two blocks away. In fact, you're probably getting paid much less, because your odds of getting out after things go sideways are almost nil.
Vincent (Tom Cruise, Collateral) is probably the most realistic prototype for a master on this list. Through the course of the film, we never get a lot of information about his background, but what little we know is that he travels. His preferred MO is to set someone up as a fall guy for his killings. He arrives in a city, receives his weapons, and intel on his targets, runs them down, and then gets out of town. He has some kind of military, possibly special forces, background. Given he's creating a reasonable cover for his activities, and given that he's getting in and out very quickly, it's plausible someone like that could exist. The most unrealistic element is just that he could carry out so many high profile killings in a single night, multiple times.
47 (David Bateson, also Timothy Olyphant and Rupert Friend, Hitman... all of them), is a bit of a nightmare scenario, but he illustrates something very interesting that has some theoretical realism to it. Now, for those who are unaware, 47 (sometimes Agent 47, or Codename 47), is the player character of the Hitman game series. (Olyphant and Friend played him in the film adaptations.) You can play the character as a complete psychopath, gunning down everyone in your path. There's not much realism in that approach. Beginning with the second game, the series started integrating a scoring system which prioritized killing as efficiently or creatively as possible. Now, creative kills were in the first game, but the only incentive was that they were often far easier than running and gunning. In it's current incarnation, the series has a strong emphasis on finding ways to eliminate targets in ways that appear accidental.
So, we have an assassin who specializes in getting in and out undetected, killing their targets in ways that appear accidental, and travels all over the world. Do you have any how hard it would be to prove someone like that existed?
Now, before I go on, I should point out, there's an inherent absurdity to the games. 47 is a 6'2” tall bald white dude with a bar code on his neck, and no one ever notices when suddenly the sushi chef gains six inches, loses his hair, changes ethnicity and happens to be the last person to be seen near the target who suddenly died of fugu poisoning. It's a running joke in the series that 47 can flawlessly blend into any crowd so long as he's wearing the right outfit.
At the same time, the hilarious thing about that joke is, it's real. When Tom Cruise was preparing to play Vincent in Collateral, something he did as personal prep was to disguise himself in a UPS uniform, and deliver packages in public. This included getting into an extended conversation with someone, without being recognized. This was in 2004, in Los Angeles, he was already a household name at this point. So, while Hitman turns the costumes swaps into a joke, there's a disturbing level of reality to that mechanic, if you look like you belong, people tend to assume you belong.
The original Hitman did have an interesting touch that the later games moved away from: You had to repurchase the weapons you wanted to take with you on each mission. So, there were no forensic ties between his guns from one killing and the next. There's a slight irony because the 1911s 47 carries are a semi-rare variant (AMT Hardballers, usually called Silverballers in game), so he's regularly discarding some fairly expensive, high-end, handguns. At the same time, he's getting paid enough to cover that, though, maybe, a slightly more common 1911 variant would probably be less conspicuous.
So, yeah, master assassins probably don't exist in the real world, and most of the assassins we know about tend to stay close to home, but if an assassin does travel, it would make identifying them significantly harder. Also, be instantly suspicious if your gardener suddenly turns into a 6'2” bald, white dude with a bar code on the back of his neck.
-Starke