Where I come from, a lot of killers get away with it, surprisingly. More than 60% in some areas.

The biggest contribution to getting caught are witnesses and becoming a suspect to begin with. Unless you have a prior record, they have nothing to match evidence to unless you actually get pulled in for investigation.

You could leave fingerprints all over the place but if you don't have any prints on record, nobody saw you, and you're never pulled in for questioning, there's nothing they can do about it.

However there's no statute of limitations for murder so if you get caught for something else later and printed, you're in trouble.