Before Andrew Cunanan shot designer Gianni Versace on the front steps of his Miami home in July 1997, Vanity Fair contributor Maureen Orth was already steeped in the mind of the serial killer. That murder is portrayed in the upcoming FX series American Crime Story: The Assassination of Gianni Versace, which is based on Orth’s book Vulgar Favors: Andrew Cunanan, Gianni Versace, and the Largest Failed Manhunt in U.S. History. At the time of the murder, Orth had spent two months reporting for Vanity Fair on Cunanan and the events that might have led to him to kill four other people before finally targeting Versace. Even before law enforcement announced that Cunanan was a suspect, Orth and the fact checkers at Vanity Fair had a hunch they knew exactly who had pulled the trigger at Ocean Drive.

In a new interview for Vanity Fair’s American Crime Story companion podcast, Still Watching: Versace, Orth reveals that once the authorities had released Cunanan’s name, “I think I was the only person in America who understood he had met Versace before. So that’s how that all started.”

The Assassination of Gianni Versace: American Crime Story, which premieres on FX January 17, was written by Tom Rob Smith—author of Child 44, who previously combined crime and romance in the compulsively watchable 2015 miniseries London Spy. And while the title name-checks Versace, the show itself—following Orth’s lead—is more focused on the mentality of his assassin: serial killer Andrew Cunanan, played by Glee alum Darren Criss. The Versace family is where FX dishes up a The People v. O.J. Simpson-worthy dose of star power, with Penélope Cruz as Gianni’s devastated sister, Donatella Versace, and Ricky Martin playing Antonio D’Amico, a model, designer, and Gianni’s longtime partner. Thanks to the reverse timeline of the story, Édgar Ramírez, whom Orth described as the “tanned, adored idol” of the late-90s South Beach scene, also gets a chance to shine as Versace himself.

Vanity Fair critic Richard Lawson and senior writer Joanna Robinson have launched a 12-episode companion podcast, Still Watching: Versace, filled with exclusive interviews, insights, and a detailed examination of not only the series itself but the cultural impact of the 1997 crime. In Episode 2 of the podcast, Orth details the genesis of her book and the challenges of getting inside the disturbed mind of a killer. The interview was conducted early Wednesday morning, before the Versace family had specifically named Orth in its latest complaint against the FX series and its treatment of Gianni’s legacy. The Versace family has long denied a number of the points covered in Orth’s book, including both the notion that Cunanan and Versace were previously acquainted and that Versace, before he died, was sick with HIV/AIDS. “The Orth book itself is full of gossip and speculation,” the Versace family's latest statement reads. “Orth never received any information from the Versace family, and she has no basis to make claims about the intimate personal life of Gianni Versace or other family members. Instead, in her effort to create a sensational story, she presents second-hand hearsay that is full of contradictions.”