Brownsville, Texas, is a town like any other on the U.S.–Mexico border, filled with the rumble of trucks and cars, shouts and muffled conversations in two languages, the wail of ambulances, and the howl of police sirens. It is very much like any other town everywhere, full of hardworking people with long histories and long memories. But in Brownsville, those people are still trying to come to terms with an event that for the last dozen years has cast a cloud over the city so black that no sunlight has seemed to get through ever since, a horrific crime that occupies the pages of Laura Tillman’s debut book, The Long Shadow of Small Ghosts.

“I came to Brownsville to learn how to be a journalist,” Tillman says from her home in Mexico City. “And I went looking for stories that would get me deeper into understanding the city and the people I was meeting.” She got what she was looking for when she happened on a communitywide debate over what to do with a dreary apartment building where a drug-addicted, mentally ill man once lived and where he somehow convinced his common-law wife that their children were possessed. With her help, he slaughtered the children, mutilating them nearly beyond recognition.

“I was never really interested in crime as such,” Tillman says. “I did more local arts coverage than local crime stuff. But something in this story got to me.” So it did, and while covering what people thought of whether the building should be razed and a memorial built, she went deep into the crime that prompted the debate, trying to understand what would drive the young man to an act of unspeakable evil—an act that, by his perverse reckoning, put him in the role of “good guy thrust into a world where evil can inhabit any form, even children.”

Her eight-year quest into those matters has yielded a fine and memorable book, an In Cold Blood for our time. But more than Capote’s book or studies of killers such as Richard Ramirez and Ted Bundy, Tillman’s foray into true crime asks readers to consider the whole constellation of mental illness and how our society responds to it, punitively more often than proactively. There are complex legal issues to consider, she writes, and then there are the many ways people have of absorbing the news of such events: she may write of mental illness, but others might attribute such evil to supernatural forces, and room needs to be made in the collective memory for all sorts of interpretations if civic life is to go on.

In the end, Tillman observes, “time may be a community’s most valuable asset when trying to comprehend a terrible act that’s shaped it.” Time passes, and fresh evils obscure old ones, which pass into history. Though it concerns a specific set of terrible events in a particular time and place, her book can be applied to countless others—and that, in itself, is a tragedy.