Terrorists in Rio de Janeiro target citizens for a series of cyberattacks and assassinations in Trigueiro’s debut thriller.

A few people in Brazil receiving “death warnings” via email or social networking becomes decidedly grimmer when motorcycle gunmen kill the ones named in the messages. When the story hits the media, anyone getting such a warning calls the cops, who suspect that the so-called terrorists are using spyware to steal people’s info. The Federal Police put Matheus Erming, head of computer forensics, on the case, and he quickly sees a similarity between the spyware and a hack used by local gangs to steal bank passwords. But someone might be thinking Matheus is getting too close to the truth: His mother, Gloria, and older brother, João Paulo, think they’re being followed. Sure enough, they both later vanish, and Matheus becomes desperate to find the culprits and save his family. Trigueiro’s novel, originally published in Portuguese, is a meticulously paced story that keeps its protagonist firmly planted in his own professional field. Most scenes feature Matheus in front of a computer or discussing ways to track down the “crackers” to lead police to whomever is spearheading the breaches and murders. The story does, however, have flashes of action, also with Matheus, a biker whose choice of ride makes the inevitable confrontation with the biker killers for hire predictable but undeniably entertaining. Trigueiro’s strength lies in developing character relationships, starting with Matheus and his obvious affinity for partner Luana. Nuanced traits help bring supporting characters to life, including João Paulo, whose blindness from a robber’s gunshot years ago is a source of guilt for Matheus, and young Guilherme, burdened by a death warning and his hapless father, a struggling alcoholic. The ending, while providing readers with a character(s) to blame, is a bit muddled, since it’s not wholly clear why the plan was even initiated. Nevertheless, there’s an impressive twist—not the mastermind’s identity but the fact that a seemingly innocent person will have no choice but to accept some responsibility for the diabolical goings-on.

Slow and occasionally jumbled but ultimately rewarding.