After all this time, Ive come across something I never knew and came here for confirmation.
So, the other day after watching "His Last Vow" for the umpteenth time, I decided to jump on Wikipedia and look up Lars Mikkelsen and then jumped to the list of Sherlock characters page.
In the description for Magnussen it states that he was the "friend" who sent the letter to John and Mary on their wedding day, the one named CAM.
It makes sense, but in all these years of watching and scrolling the subs. I've never seen that mentioned before.
So I'm just wondering is it true and when was this revealed? Maybe I missed some dialogue or something. I'm also just a bit shocked it was set up that early, if it is true.
But also glad to find something new after all this time as well.