Confessor

We’re not sure how he did it, but all of the evidence points to this guy who walked in and confessed to the murder.
There’s one problem, though. The murder took place in the Fifteenth Century. A simple assassination in Rome. A bishop history barely remembers.
Fingerprints, DNA, and a painting from the time confirm it’s him.
Not just a long-distant ancestor. It’s actually him. He did it.
There’s no statute of limitations on murder and he’s confessed to the crime, so we’re going ahead with the trial.
Maybe he’ll tell us how he did it. And maybe he won’t.