The author and lawyer Scott Turow has never forgotten a harrowing conversation he had long ago with the mother of a young man charged with murder. Turow had successfully defended him in an earlier, less grave case, but this time he was clearly guilty.

It was a tragedy on many levels. But what struck Turow about the conversation was the mother’s fierce, primal love for her son despite everything. “She was just torn apart,” he said.

That memory was floating in the back of his mind as he conceived his latest novel, “Presumed Guilty,” about a high school student accused of murdering his girlfriend on a camping trip gone awry. The plot was inspired, too, by the 2021 murder of Gabby Petito, killed by a boyfriend whose parents closed ranks to protect him.

“I’ve always been struck by how terrible it is, what a shattering experience, for a parent when a child gets accused of a serious crime,” Turow said. “They think, ‘Is my love for this child so huge that I can’t recognize that he or she is a monster?’”

“Presumed Guilty” is Turow’s 13th novel, and the third to feature the former prosecutor (and now former judge) Rusty Sabich. Fans of Turow’s emotionally astute, legally complex and compulsively readable novels will remember meeting Rusty for the first time in the 1987 blockbuster “Presumed Innocent,” widely considered the gold standard for the modern courtroom thriller. (He’s also been in a 1990 movie and a 2024 mini-series, played by Harrison Ford and Jake Gyllenhaal, respectively.)