I was kind of inspired by a television programme I was watching recently - I won't spoil it by saying its name.
Let's say my friend committed a murder and wanted to get away with it. So together we conspire to frame me for the crime. By subtly "allowing" the evidence to point to me, all the time I protest my innocence to the police, but I am careful never to do so to their absolute satisfaction, e.g. acting like I'm unable to explain certain pieces of key evidence.
After much investigation, they are confident that in spite of my protests, it was me, so we go to trial where I plead "Not Guilty". Then, during the trial, a new piece of evidence is suddenly "found" that proves I could not have possibly committed the crime! (e.g. Someone who happened to be recording a video on their phone with a clock in the background as I walked past or something, showing me somewhere else at the time of the murder).
So I'm acquitted.
So do the police just give up now? Was that their only chance? Or will they start a new investigation to try to find who really did the crime, with another possible trial of another suspect?
I've tagged several countries that I'm familiar with, but if the answer is different in different jurisdictions then that would be interesting too.
For those curious the show I was talking about is
You Don't Know Me Not exactly the same thing that I'm asking about happens, but along similar lines.