With my pups, if I find something chewed up, and I show it to them both. The guilty party always shows it!
I've had it work a few times!! I've picked up something and showed Buddy, and he just looks at me like "What!? I didn't do it" Then I look at Sierra and her ears are pinned back and she's sneaking into another room. And I've done it the other way, and I swear Sierra just laughs when Buddy's done something!!
I don't know if it's true... but I swear I can tell which of my dogs have done something wrong!

I've also had it when it's been a group effort and they BOTH run and hide!!