The return address is 'Charlie Wallace (yes Drake he used your last name and his dog's first name), the address if investigated at all is a legit address in Boston. It's a church. Nothing out of the ordinary. And nothing that anyone reading it or investigating at the jail (because they like to read inmate mail!!) would find all that fishy. And nothing cluing anyone in to knowing it was from the police chief! Wren would obviously know it was from Kyle. The back of the envelope has a paw print!
Hey you,
We're thinking about you, keep your chin up. I swear everything is gonna be alright. I promise. We miss you, and hope to see you real soon. Smile for me.