Cracking Cuckoo’s code: TIME speaks to forensic linguist who analyzed Rowling’s secret book

In a story that unfolded much like a detective investigation itself, this past weekend The Sunday Times revealed that the long-released crime novel The Cuckoo’s Calling was written by J.K. Rowling, under the pseudonym Robert Galbraith. But before the Times reached out to the publisher following a mysterious tip on Twitter, they launched a private investigation of their own to find linguistic similiarites between the book and Rowling’s other works. TIME spoke to one of the experts involved in this analysis in a facscinating recent article.

Patrick Juola, a computer science professor at Duqeusne Univeristy, utilized a computer program to analyze word usage in The Cuckoo’s Calling and compare it to four other texts, including Rowling’s The Casual Vacancy. This science is more often applied to legal cases, but is made easier to apply to literature with the existence of e-books.

The free, publicly available program pulls out the hundred most frequent words associated with an author, eliminating rare words such as the magical vocublary seen in the Potter series or character names.

This scientific approach is more effective in Juloa’s opinion versus looking for impressions and styles, because people using the latter approach “will just find whatever they’re looking for.”  But while Rowling stayed successfully out of the public eye for nearly three months, it isn’t an easy task for an author to truly disguise themselves beneath linguistic departures.

“Word length, for example, is something the author might think to change…what the author won’t think to change are the short words, the articles and prepositions,” TIME writer Lily Rothman says. “Juola asked me where a fork goes relative to a plate; I answered ‘on the left’ and wouldn’t ever think to change that, but another person might say ‘to the left’ or ‘on the left side.'”

The information gathered from the program was not concrete, and like DNA similarities in a crime scene, was advised to only be considered as enough potential evidence to press the publisher for answers. In this case, the evidence led to a correct conclusion and an eventual statement from Rowling.

The Cuckoo’s Calling continues to climb bestseller lists as book sellers struggle to meet the unexpected demand. Have you picked up your copy yet? Let us know in the comments!