Dear Sherlock,
Greg and I have kept in touch, if you didn't already know, and three days ago he rang me and called me out to a crime scene. I know what you're thinking: "John at a crime scene, expected to miraculously deduce the answer?" But apparently the police are lost without their consultant detective, so they turned to me.
It's not like I was of any help to them. I looked at the body, but I'm not you, Sherlock. Nothing stood out to me, and there was none of that genius that you had. I think they just hoped that I'd picked up something from you. But you always surprised me, and I could never be as clever as you.
Anderson was there, like he always is, and he kept spouting nonsense at me whilst I was examining the body. I told him to shut up for you. I thought you'd appreciate that. I think Greg might have smiled, but he covered it up pretty well.
There's no use in me telling you what I saw on the body, or whether they were wearing a wedding ring or not or even who they were. Because I won't have noticed anything of importance that could possibly help you to solve this case. I know you would have had the answer within five minutes of entering the room.
Greg... Well... I'm not sure what he thinks about you. I still wonder whether he believes in you or not. When we were at the crime scene, I heard him say: "I wish Sh-" And then he caught himself, as though he remembered that you were apparently a fake and could no more have helped him than I could.
But I know you weren't a fake. I know because I knew the real Sherlock Holmes. The Sherlock at home, who would run around screaming for cigarettes, sulk on the sofa for days on end, put body parts in the fridge with the food, shoot at a smiley face on the wall and walk around in only a bedsheet. That was the real you, and I don't think that's possible to fake.
Your John.