An anonymous tweet unmasked beloved Harry Potter author J.K. Rowling as “first-time novelist” Robert Galbraith, author of The Cuckoo’s Calling.

Rowling’s first book for adults, The Casual Vacancy, came out in September 2012. It was saddled with pre-release excitement and high expectations; it garnered mixed reviews. Meanwhile, Galbraith's book was so well-reviewed, many people did not believe it could have been written by a novice. 

It wasn’t.

The whole story came to light when a journalist at the Sunday Times tweeted that she enjoyed The Cuckoo’s Calling but had a hard time believing it was written by a first-time author. Around midnight, according to the New York Times, she received a tweet back from an anonymous account saying the book was written by Rowling. 

When asked for proof, the account wrote back, “I just know.” The account was then deactivated. The user deleted all traces of his or her presence online. Richard Brooks, the Times' arts editor, investigated. Comparing the two books, the Times wrote:

Both books shared the same agent, publisher and editor in Britain, for example. It seemed particularly odd, he said, that the editor, David Shelley, would be in charge of both someone as important as J. K. Rowling — a very big job, indeed — and someone as seemingly unimportant as Robert Galbraith. … [H]e sent copies of “The Cuckoo’s Calling,” “The Casual Vacancy” and the last Harry Potter novel, “Harry Potter and the Deathly Hallows,” to a pair of computer linguistic experts, who found significant similarities among them.

Rowling confessed in a statement:

I had hoped to keep this secret a little longer, because being Robert Galbraith has been such a liberating experience. It has been wonderful to publish without hype or expectation, and pure pleasure to get feedback under a different name.

From there, the publisher confirmed that Galbraith was Rowling. But who sent that initial tweet? The publisher, hoping to turn a flop into a bestseller? Rowling herself? One Mr. Harry Potter, not actually fictional? The mystery continues.

H/T New York Times | Image via Daniel Ogden/Flickr