And note that the defence attorney accused the prosecution of sending the letter. Why?
It sounds like the judge is running a going out of way to follow procedure and avoid a later mistrial. No one is “going after” the defence!
It didn't work. At the same time the attorney is certainly entitled to know who his accuser(s) might be so he can sue their pants off (a pun guys, a pun ~ what a thread to use that one eh).