The Winds of Winter: Who wrote the letter that killed Jon Snow?
Did Melisandre write the Pink Letter?
Another candidate to write the pink letter is the red priestess Melisandre, who is still at the Wall with Jon when he gets the letter and is killed by his brothers. Melisandre does have a history of bending the truth and manipulating people, and she has a motive to help Stannis win the Battle of Winterfell.
There is a lot working against Melisandre though. The major issue is that we get a POV chapter from Melisandre in A Dance with Dragons and there is no mention of the letter or her intention to make a move against Jon. In fact, her POV chapter reveals that the visions she sees in the fire are very inaccurate most of the time, and if she did write the letter, she would have to have gotten a lot of the information in it from her visions. Otherwise there is no way for her to know about Reek and Ramsay’s wife. Since it would be impossible for her to know a lot of the information in the letter, Melisandre probably did not write it.
Did Melisandre write the Pink Letter? Extremely Unlikely
Did Barbrey Dustin write the Pink Letter?
Barbrey Dustin is the Lady of Barrowtown and one of the norther lords currently in Winterfell serving the Boltons. She has a pretty interesting backstory; she had a romantic affair with Ned’s brother Brandon Stark in her youth. But Brandon’s betrothal to Catelyn Stark ended their relationship; when he rode south to marry Catelyn, he was executed by the Mad King.
Barbrey has harbored ill will against the Starks ever since. She even says that she will do whatever she can to stop Ned Stark’s bones from being respectfully laid to rest in Winterfell, only because he was married to Catelyn.
So her hatred of the Starks already makes her an unlikely candidate for writing the pink letter, but Barbrey has a motive because she also hates Ramsay Bolton. Back in the day, Roose Bolton was married to Barbrey’s sister, and they had a son named Domeric who was the heir to the Dreadfort. When Domeric learned he had a half-brother, he sought out Ramsay, but soon after died of a bowel sickness. Barbrey and even Roose, suspect that Ramsay poisoned Domeric so he could have a better claim as Roose’s heir.
Barbrey may be involved with the northern conspiracy or could have other intentions. Either way, she doesn’t seem a candidate to write the pink letter, unless there’s something about her we don’t know yet.