Word broke over the weekend that J.K. Rowling, author of the “Harry Potter” series, had secretly penned a new crime novel, “The Cuckoo’s Calling,” under the pseudonym Robert Galbraith. Initially, an unknown source tweeted a Sunday Times of London writer that Rowling had penned the book, but the leaker’s identity remained a mystery until now. On Wednesday, Rowling’s own trusted lawyers, British firm Russells Solicitors, announced that the leak had come from one of their partners.

According to a statement from Russells Solicitors, only a few people at the firm knew the real secret behind Robert Galbraith’s identity, including partner Chris Gossage. Apparently eager to impress people, Gossage told his wife’s best friend Judith Callegari that Rowling was in fact the author of “Cuckoo’s Calling.” Soon after she learned the secret, Callegari tweeted a Sunday Times writer that Galbraith was really Rowling, setting off the entire chain of events that led to Rowling publicly acknowledging she penned "The Cuckoo's Calling."

Russells Solicitors has apologized for the leak. The law firm clarified that the leak of Rowling’s authorship was entirely accidental and in no way part of a marketing ploy to increase sales of “Cuckoo’s Calling,” as some have speculated.

“We, Russells Solicitors, apologise unreservedly for the disclosure caused by one of our partners, Chris Gossage, in revealing to his wife's best friend, Judith Callegari, during a private conversation that the true identity of Robert Galbraith was in fact J.K. Rowling,” the statement reads.

“Whilst accepting his own culpability, the disclosure was made in confidence to someone he trusted implicitly,” the statement continues. “On becoming aware of the circumstances, we immediately notified J.K. Rowling's agent. We can confirm that this leak was not part of any marketing plan and that neither J.K. Rowling, her agent nor publishers were in any way involved.”

In response to Russells Solicitors’ statement, Rowling released a response of her own, stating that she was extremely disappointed that the leak came from one of the few sources she trusted with knowledge of her pseudonym. Rowling also again acknowledged that she had hoped to remain anonymous in her authorship of “Cuckoo’s Calling” for some time.

“A tiny number of people knew my pseudonym, and it has not been pleasant to wonder for days how a woman whom I had never heard of prior to Sunday night could have found out something that many of my oldest friends did not know,” Rowling said in a statement.

"To say that I am disappointed is an understatement," she continued. "I had assumed that I could expect total confidentiality from Russells, a reputable professional firm, and I feel very angry that my trust turned out to be misplaced."

Rowling may not be happy with her law firm’s breach of trust, but she certainly has to admit that the revelation did wonders for her sales. Only hours after word broke that Rowling was the book’s author, sales of “Cuckoo’s Calling” skyrocketed by 507,000 percent on Amazon, launching the book into Amazon’s best-selling novel for five days straight.