Selection bias is a cheap canned answer, but it doesn't make any sense here. Sensational unsolved crimes make the news. The public hearing about crimes isn't conditional on those crimes being solves. Arguably some of the most enduringly notorious crimes are the ones that go unsolved.
The Zodiac Killer; never been caught. "D.B. Cooper", never caught. The presumed murder of Jimmy Hoffa, unsolved.
I happen to know somebody who was involved in the investigation of highly professional heist. The bank wanted to keep it quiet, and I can't find much other than this one article about the incident. I was gonna call it movie-worthy, but it's not, because there were no salacious details, no close calls, just in&out and no funny business.
Sure, but there is really no shortage of known unsolved crimes.
> The police does not put out press releases repeatedly with 'we got no leads'.
They do, in all the cases I listed they've asked the public for help for years. Certainly they don't do that for crimes they don't know occurred, but there is no shortage of known crimes that are very publicly unsolved.
For that matter, there are also a whole lot of missing person bulletins soliciting information from the public. Many of them might be murder victims, but it isn't known whether they are really alive or dead, let alone murdered. The public is nonetheless asked for information.
> Sure, but there is really no shortage of known unsolved crimes.
That's certainly the nice way to put it -
"If you're murdered in America, there's a 1 in 3 chance that the police won't identify your killer. To use the FBI's terminology, the national "clearance rate" for homicide today is 64.1 percent. Fifty years ago, it was more than 90 percent." ... "Criminologists estimate that at least 200,000 murders have gone unsolved since the 1960s"
Yes, police are pretty good at solving "the spouse did it" crimes, the most obvious sort. When the victims were chosen randomly, the clearance rate becomes abysmal. They're also bad at solving crimes when the victims come from the marginalized fringes of society. Jack the Ripper is a famous unsolved case of a serial killer who targeted prostitutes more than a century ago. Modern examples include the Long Island killer, the Eastbound Strangler, and plenty more.
When the existence of such a serial killer is recognized, it tends to make the news at least regionally. Sometimes they become internationally famous for many years. But to my point, the public hearing about it is not contingent on the culprit being caught. If anything, the ones who are caught fast and easy tend to make the least amount of news. You can 'juice' unsolved crimes for stories a century after the fact, but stories that follow the "husband did it and we caught him" format tend to disappear from the news after the culprit has been sentenced.
Except for when the husband didn't do it after being convicted, where it turns out the wife was having an affair with a golf pro, and someone comes in and kills them both. I bet that one would even lend itself into making a great movie.
Still shocking to me that nobody looks at the life insurance broker who knows that the spouse would be vulnerable to a sure conviction if the other spouse was found dead within the next few months after opening the policy
The Dutch police has a cold case team, yes. For cold cases ( there is even a word for it ) which have not seen progress or public attention for year, some even decades.
I think most police forces have one. A decade might mean there's new tech that can move the case forward or the criminal got caught for something else and it's just a matter of connecting the cases.
This is not always the case... the DoJ reminds me of a sales organization. Crimes are sales leads. Publicized leads are usually very close to being closed(solved).
That doesn't always work though - the crime may be something the public is aware of, and then the pressure to "close" the lead is even greater. There are numerous "big" crimes that the public has no awareness of though.
The Zodiac Killer and D. B. Cooper are notable exceptions. And there are probably a bunch more.
It seems statistically unavoidable that there are always going to be some big cases that go unsolved. It'll probably become less and less common - especially since it seems inevitable that nearly all DNA will eventually be traceable via genetic genealogy databases - but some crimes just won't result in any DNA or other significant evidence being left.
The Zodiac Killer; never been caught. "D.B. Cooper", never caught. The presumed murder of Jimmy Hoffa, unsolved.