> 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"

https://www.npr.org/2015/03/30/395069137/open-cases-why-one-...

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.

What, would you have an entire movie with the husband sitting in prison slowly whittling away the time with a rock hammer? Never would get funded.

Cast Harrison Ford as the wrongfully accused husband. Have him escape after his bus to the prison crashes, then have Tommy Lee Jones as a US Marshal chase Ford down while Ford is trying to prove his innocence.

Might just make for a blockbuster 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

What is the broker’s motive?

for the lulz?

fbi says there are over 2,000 serial killers free in the US

we dont know nearly enough of them to know motivations or even assume thats a prerequisite

A random person doing it for the lulz is already likely to get away with it, at least for a while. No need to do that much prep.

Clearance rate for rape: 34.5% (65.5% unsolved)

Source: https://ucr.fbi.gov/crime-in-the-u.s/2017/crime-in-the-u.s.-...

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.