Officially, the first corpse turned up in 1993. Alma Chavira Farel was 13 years old. She'd been raped, sodomized, beaten and strangled—and her body was the first of what would come to be called the feminicidios. After a decade in which the death toll continued to mount, Amnesty International estimated that as many as 400 women had been killed in the Mexican city of Juárez. Almost all were poor young workers from the assembly plants sprouting on the border as U.S. companies began taking advantage of low wages and tax incentives offered by the North American Free Trade (NAFTA) agreement signed the year that Chavira died. The mystery of their murders has never been solved.

The tragic saga of the dead of Ciudad Juárez—directly across the river from El Paso, Texas—has been covered by those who care. Amnesty called the murders intolerable and condemned the Mexican government for ignoring them; other human-rights groups have leveled similar criticisms over the years. Ted Botha's new book "The Girl With the Crooked Nose" (Random House) looks at the crimes from a different perspective. The book, which Botha describes as a nonfiction thriller, views the murders through the eyes of Frank Bender, a Philadelphia forensic sculptor who puts faces on the dead. Bender's job is to take a skull and reconstruct the features of its owner. For reasons he doesn't fully understand, the Mexican police on the case ask him to help identify some of the feminicidios. He winds up spending days in a Juárez hotel room with crumbling skulls, facing down death threats and an infection from the bad water as he tries to create identifiable likenesses of the dead women.

TV shows like "CSI" and "Bones" have lent a glamour and excitement to forensics. Botha's book offers a real-life glimpse of the grunt work, bureaucratic politicking and poor pay as Bender tries to win recognition for what was once an unrecognized specialty. Bender moves from commercial photography to crime work almost by accident. A free spirit (the self-portrait dominating his work space shows him nude, his penis depicted in three dimensions), he saw his first skull when he tried to cadge free anatomy classes by studying the bodies at the Philadelphia medical examiner's office. Shown the body of a woman—toe tag No. 5233—whose head was partly shot away, he realizes that he can sculpt his vision of what she once looked like. So accurate is his depiction that when photos of the bust are released the victim is identified as one Anna Duval.

Botha's writing is lively and versatile. Since we first met as young reporters covering apartheid in South Africa, he added a diverse body of work to his credit. Previous books include an account of an overland odyssey through Africa ("Apartheid in My Rucksack") and a study of New Yorkers who collect what others have dumped on the sidewalk ("Mongo: Adventures in Trash"). "The Girl With the Crooked Nose"—named for one of the Juárez victims—was, he says, a "baptism by fire" into the world of police work. "When I first started the book," says Botha, "I didn't know the difference between an anthropologist and a pathologist." He learns fast, though, and skillfully weaves his narrative back and forth between Bender's early work and the Juárez cases that would come to obsess him in spite of the risk. On one occasion, Bender even rashly tells his Mexican police contact his belief that the killings were part of an evil alliance between organized crime and the state police. "I think the police rape and kill the women to prove themselves to the drug cartel," he says. "That's how they show their loyalty. Let's face it--the cartel isn't going to use a policeman unless he proves himself." Later, trying to sleep in his isolated apartment in a former police academy, he realizes that "perhaps it hadn't been wise" to tell a state policeman his theory that his colleagues could be murderers.

Bender's real skill is in the intersection between art and science. Skulls can only reveal so much, especially if parts have been beaten or shot away. In one case—a skeleton found in a thicket in North Philadelphia—Bender takes his inspiration from a Ship 'n Shore blouse found near the body. The classic feminine brand wasn't typically worn in that part of North Philadelphia, leading Bender to surmise that the victim was an ambitious young woman. He portrays her with her eyes looking optimistically upward, her hair in a pompadour that he instinctively feels suits her face; he dubs her the Girl with Hope. She remains unidentified, though, and eventually becomes part of an exhibit in Philadelphia's renowned Mütter Museum. There she might have stayed had not a local office cleaner seen a picture of the head in a discarded newspaper. When the cleaner visits the exhibit, she recognizes the bust as bearing a distinct resemblance to her niece. Her tip leads police to dental X-rays that confirm her identity as Rosella Atkinson, aged 18 when she went missing.

Inevitably, not all of Bender's cases have such conclusive endings. The Juárez murders have never been properly solved; the girl with the crooked nose remains nameless. And if Bender's talent brings him fame, it fails to bring fortune. Indeed, Bender makes so little money from forensic sculpting that at one point he is forced to take a job on tugboats. Botha correctly shies away from trying to romanticize Bender, documenting his affairs and marital problems in the same dispassionate tones that Botha uses to describe his work. While this matter-of-fact style prevents the corpse counts from becoming too gruesome, it is less successful in conveying a nuanced portrait of the sculptor himself. Readers may not come away from the book feeling they've fully grasped the essence of Bender, but they certainly won't have that feeling about the value of his work.