Criminal Mind

The stranger wore a white rabbit fur toque for its symbolism of purity. Inside his hobo sack he carried necessary accouterments of the wandering class and various weapons, including a knife and wooden clubs. Eventually, he adopted a dog and a pet magpie, and toted an accordion. The instrument he could not play well. The animals he clubbed to death as a horrified witness looked on. He was Joseph Vacher, a former soldier who roamed the French countryside from 1894 to 1897, killing more than twice as many people as Jack the Ripper, and the antagonist of Douglas Starr’s absorbing historical true-crime book, “The Killer of Little Shepherds.”

In alternating chapters, Starr tells the story of Vacher’s life (and sadistically brutal crimes) and that of the criminologist ­Alexandre Lacassagne, whom the author credits with modernizing forensics. Their stories come together toward the book’s end, when Lacassagne is summoned as an expert to help determine the outcome of Vacher’s trial.

It is often said that a story, like a crime, is in the details, and Starr, whose previous book was called “Blood,” is certainly not one to hold back in delivering the gruesome facts of Vacher’s infamous deeds. He recounts how Vacher repeatedly stabbed and stomped one victim, a 21-year-old woman wearing “Molière shoes,” taking care to carve out the areola of one of her breasts. Elsewhere, he tells how Vacher eviscerated a boy “like a hunter gutting an animal.”

Lacassagne had his own knack for specificity. The head of the Institute of Legal Medicine at the University of Lyon, he analyzed the various stages of putrefaction to determine the timing of a death, figured out how to match a bullet to a gun and studied patterns in knife wounds to determine the attacker’s handedness. He was so fascinated by criminals that he analyzed their tattoos to better understand their various subcultures. Eventually, he had these images reproduced on a set of dinnerware.

“Societies have the criminals they deserve,” Lacassagne said. This can certainly be stated of Starr’s belle époque France. Rural forensic procedures were primitive. Autopsies sometimes took place on the kitchen table of a victim’s home. The police often relied on rumor and innuendo when conducting their investigations. The court system was a popular means for settling ­grudges. As was mob violence.

It was the perfect setting for the roving Vacher, who eluded capture by walking up to 20 miles in a single day, traveling under the belief that God protected him until several people managed to subdue him after an attempted rape.

In a highly publicized confession, Vacher described 11 murders, mostly of teenagers, in towns more than 600 miles apart. He played up his mental state in a suspicious attempt to manipulate his defense.

While Vacher’s sanity and criminal responsibility were at issue in his internationally publicized trial, questions about his mental state continued well after his conviction and execution.

If societies have the criminals they deserve, perhaps it can be said that crimes inspire the writers they merit. Starr could easily have used Vacher’s killings as a means of driving home a point about his hero, Lacas­sagne, and left it at that. He is good enough, though, to show the impact these murders had on the victims’ families and on the villages where they took place, and to demonstrate how they prompted larger questions about the origins of criminality for La­cassagne and his colleagues.

But the moral significance of these inquiries — trying to isolate the roots of criminality is, at heart, a quest to understand the origins of evil — comes as an after­thought that slipped from the path of Starr’s own densely detailed wanderings. Nonetheless, his thought-provoking journey, through the strange underbelly of a vividly rendered France, lingers in the reader’s memory.