Do you know if it actually happens that the police (or similar force) would hire or work with a criminal with great fighting abilities? Because they would be expendable? Or is that just a trope used in fiction? I can hardly imagine that it’s true, but informants are a thing (from what I know), so such a kind of arrangement doesn’t seem to be too far fetched?
If I’m being blunt, I don’t remember seeing, “great fighting abilities,” being cited in one of those examples. Usually, what you’ll see is something like, “they’re a great thief,” or, “they’re a genius hacker,” not, “they’re an artist with a crowbar.”
If a police force needed combat specialists for something, they already have those. Both in their own SWAT units, and also from ex-military members of their own organization. (It’s also distinctly possible that these groups would overlap. So you can get an ex-military SWAT team member.)
The irony is, you’d be hard pressed to find a real criminal, “combat specialist.” Violence doesn’t pay the bills. It is a tool that can used during the commission crime, but violence is only one aspect.
The best you can hope for is, like with cops, that your criminal has a military background. That’s not far fetched. They’ll understand how to fight and manage their foes, but by necessity, their specialty will be something that actually pays.
For law enforcement, violence is a tiny part of the job. Far more often, they’ll be showing up after the violence is over, and piecing together what happened. When looking at the aftermath of a violent crime, having a, “combat specialist,” on hand isn’t going to be that useful. After all, investigating a violent crime is a detective’s job. They are specialists. There’s not much insight a “combat specialist” can give a detective who spends their days studying murders for clues. For a detective, violence isn’t mysterious.
Now, reformed career criminals do have a real option selling their expertise as consultants. When you’re looking to shore up your company’s security, being able to hire a former criminal to learn about the weaknesses in your organization can be a major boon. And some reformed criminals do offer consulting services. Want to learn how a professional would break into your building? Hire an ex-thief. Want to know how a con artist would get access to your client data? Learn about social engineering from the people who used it.
There’s an entire field of security called Penetration Testing (or just “Pen Testing”), where you hire someone to break into your security. This could be a hacker, or a thief. At that point, you’re paying them to find ways to break in, so you can use the information they find to improve your security. Kevin Mitnick is one example, but there are a number of others.
Law enforcement organizations may choose to use outside consultants for specialized training. This could include people with criminal backgrounds explaining their methodology. However, in most cases, this would be things things the police are already familiar with from their own investigations.
What you would not see is the cliche of an ex-criminal who works alongside detectives in their investigations. That doesn’t happen. Any half-sentient defense attorney would be able to rip apart an investigation which included criminals as investigators. Because of cultural prejudices, criminals (and former criminals) don’t have a lot of credibility. While you can argue the merits of it, this is a cultural norm. As a result, criminal witnesses and investigators are far less useful than ones with a clean record. The closest you’d get are informants.
Informants are a complex topic on their own. The short version is, they don’t assist in the investigation, they report information they have to the police. In the simplest terms, they are just another witness, the only unique thing about them is that the police have “cultivated” them. They may enjoy informal protection from prosecution over minor crimes if they’re useful. This, in turn, means their credibility is virtually non-existent in court, and as a result, the police need to justify their findings.
With a criminal investigation, it’s not about the end result; it’s about creating a complete picture of what happened, and showing how you put that together from the available information. The entire concept of, “expendable,” doesn’t apply, because it’s all part of the picture.
Using criminals because they’re expendable is a thing, just not for law enforcement. For example, if you’re working for an intelligence agency, having criminals you can use and discard can be situationally useful.
Again, you’re probably not going to grab criminals for their combat expertise. If your operation requires combat specialists, you’re better off tapping your nation’s Tier One operators. The only thing a criminal combatant would be good for is a distraction.
Ironically, that same lack of credibility makes criminals very appealing for spies. If something goes wrong, if the criminal tries to burn them, who’ll believe a burglar? Especially when “they’ll say anything to save their own skin?”
Since someone will probably mention it, one scenario where you’d have cops working with criminals is when the cops are also criminals. The widespread corruption within Los Angeles County Sheriff’s Department comes to mind as a good example of this. However, at that point, you wouldn’t be looking at a real investigation, you’d basically be looking at criminals (some with badges, some without), either trying to protect themselves or attack their rivals.
On the whole, the criminal working with cops motif is a method to spice up “Odd Couple” cop teams. It has very little relation to reality, and is entirely about trying to generate drama between the characters. There are ways an ex-criminal can put their experience to use without breaking the law, but getting partnered with a by-the-book, “too old for this shit,” cop isn’t one of them.