No one has been publicly and definitively identified as the person who wrote the anonymous letter to John F. Kennedy Jr. about Carolyn Bessette, at least in any credible, on‑the‑record source as of early 2026.

What we actually know

From reporting tied to the FX series “Love Story: John & Carolyn” and the underlying book by biographer Elizabeth Beller, the situation is described like this:

  • John received a letter early in his relationship with Carolyn that attacked her character, calling her a user, heavy partier, and someone chasing status and fame.
  • The sender is described as a friend of his from the same rarefied world: elite boarding schools, Ivy League, and wealthy New York families.
  • At the time, the letter was presented to him as effectively anonymous; he knew it was from a friend, but not which one.
  • The letter contributed to a serious rupture in their relationship for a period, before they eventually reconciled and later married.

Did Elizabeth Beller or the show name the author?

  • Coverage of Beller’s book and the FX series makes it clear she does not name the person who wrote the letter.
  • Beller’s account says that Carolyn eventually figured out who wrote it and then cut that person out of her life , but Beller still withholds the identity from the public.
  • Recent commentary videos and articles about “the anonymous letter that broke up JFK Jr. and Carolyn” retell this story and emphasize that it came from John’s own social circle, but they likewise do not provide a real‑world name backed by hard evidence.

What about online theories and forum gossip?

  • Fan forums and Reddit threads discuss “the letter” in the context of the show, Beller’s book, and gossip about JFK Jr.’s circle, but they mainly repeat that a friend investigated Carolyn and wrote a harsh report‑style note.
  • These discussions speculate about motives and what was written, but they do not reliably identify a specific person, and any names tossed around there should be treated as unverified rumor rather than fact.

Bottom line

So, to answer your question “who wrote the letter to JFK Jr. about Carolyn?”:

  • Publicly available, credible sources say it was a friend from his wealthy, prep‑school/Ivy League New York circle ,
  • But no reputable source has disclosed the friend’s name , and the biographer whose work underpins the current “Love Story” coverage explicitly leaves the author unidentified, beyond noting that Carolyn later realized who it was and cut them off.

Information gathered from public forums or data available on the internet and portrayed here.