Yes. You were taught them. For me, it's more just having studied Psychology and knowing human behaviour/nature and common freakin' sense very well.

Back where I'm from we had a keystone cop fuck up years ago too. A guy from a very well-known family killed his father in his office. Our small-town cop shop was used to harassing kids, not solving crimes. Just like the Jon Benet case, they didn't secure the scene. I mean, I'm no expert, but I'd think that's probably day 1 of police school.

The son was found guilty, but it was overturned on appeal because the cops messed it up so bad.