London: The mystery has been solved.
A British law firm says one of its partners inadvertently leaked the identity of JK Rowling as author of mystery novel "The Cuckoo`s Calling."
The Sunday Times newspaper revealed over the weekend that the "Harry Potter" author had penned the book under the pseudonym Robert Galbraith, after receiving a tip-off on Twitter.
There had been speculation that Rowling or her publisher were behind the revelation. Since Rowling was outed as the author, the novel has topped best-seller lists.
But today law firm Russells said one of its partners had let the information slip to his wife`s best friend the woman behind the tweet.
The firm said "we apologise unreservedly" to Rowling.
Rowling said that "to say that I am disappointed is an understatement."