Nah, it applies to the person trying to get away with the murder. People will do really, really intricate jobs of trying to cover up, then slip up because like, they leave a receipt in their car that accidentally breaks their alibi.

My favorite get away with murder stories are the imperfect frame up type stories. So commit a crime and lay a trail of bread crumbs to a false path that will be picked up by the investigators and then later on easily refuted by yourself - because you did it but not in the way you're accused of.

A clever murderer will disguise the murder as an accident, suicide or natural death. It will not even show in the stats as unsolved.

I got the idea from fiction (specifically Dorothy Sayers), but the number of murders Harold Shipman committed before anyone even noticed makes it plausible that people with relevant expertise (doctors, pharmacists, cops, etc.) could easily get away with murder. If Shipman had stopped after the first 100 or so he would have.

That's from Body Heat, said by Mickey Rourke to William Hurt. "...you got fifty ways you're gonna fuck up. If you think of twenty-five of them, then you're a genius - and you ain't no genius." (But a million sounds closer to the truth.)

Even if you can think of 10 relatively uncorrelated reasons, that lets you catch the genius murderer 1-(1/2^10) of the time, which is quite good.