Having watched a few FBI interrogations and other true crime related videos there certainly are such proofs.

I have a few of these come to mind, like the dude who killed his ex, took the house surveillance cameras down after the facts but didn't know they were backed up on servers, he was caught with the cameras in his truck shortly after. Most of these publicly known cases have a ridiculously long trail of proofs actually

I'm not saying mistakes don't happen, they obviously do, but in many cases it's extremely easy to prove if someone's guilty or not.

> Even if the suspect is on camera confessing.

That's not enough in most countries