Oh, I just caught something in 3×12- Killian says to Emma after she asks what the story with the new curse is “We dont know”. He said WE, Not I- so whomever *cough-Neal-cough* it is, he must still be in contact right? It would also explain why he out of the blue refuses to talk about what went down during that year, when he has been open & to the point about everything else (ie.I doubt Killian would say, “yeah, I spent time looking for the JR, to find away back to you, then a little bird was sent by your ex’s, father’s girlfriend or ex, who is now 1/2 a DO or a flying monkey man, because he used dark magic to try bring his father back & to get back to you & Henry, so I gave up my ship to get back to you, rescue you from marrying a flying monkey man & to save your family”). If he really didnt know who sent the letter & memory potion, he would surely have said “I dont know”.