Two intense mysteries feature terrifying serial killers—and the cunning detectives who catch them.

Authors Eva García Sáenz and C.S. Harris balance shocking violence with the slow and steady thrill of watching a detective meticulously unravel a case.

Sáenz’s chillingly graphic The Water Rituals follows Spanish inspector Unai López de Ayala—better known by his nickname, Kraken—on the trail of a killer who has been drowning pregnant women in ways that mimic a 1,000-year-old ritual. 

Kraken, a behavioral profiler, is especially taken aback when he learns that the first victim is his former girlfriend, graphic novelist Ana Belén Liaño. Her body is found hanging upside down by her ankles, her head submerged in a Celtic cauldron of water. 

Unable to speak because of a traumatic brain injury (from his first adventure, The Silence of the White City), Kraken can only communicate with his fellow detectives by writing his thoughts on scraps of paper. The trauma of Ana’s death sparks a series of flashbacks as he recalls their relationship, and the memories prompt him to seek clues to her death as he tries to regain the ability to speak. News that Kraken’s boss, Deputy Superintendent Alba Díaz de Salvatierra, may be pregnant with his child ups the tension and the stakes as his pursuit of the killer continues.

Sáenz, who began her career by self-publishing before becoming an award-winning short story writer, maintains a tight point of view from Kraken’s perspective, creating a claustrophobic, psychologically intense experience for readers en route to a dramatic finale.

Harris’ novel What the Devil Knows is equally brutal. The novel opens in 1814 London, three years after the real-life Ratcliffe Highway murders and decades before the more notorious Jack the Ripper slayings. The lead magistrate in the Ratcliffe Highway case, Sir Edwin Pym, has been killed in the same manner as the Ratcliffe killer’s victims.

Lead investigator Sebastian St. Cyr immediately voices his concern to fellow investigators: “You assume this murderer has a logical reason for what he does. If I had to guess, I’d say it’s more likely whoever did this simply enjoys killing.” So begins the methodical, purposeful pursuit of a killer who has no qualms about what he does, whether he is the actual Ratcliffe Highway killer or, as Sebastian muses, a copycat “deliberately modeling his acts on the sensational murders of the past.”

What the Devil Knows is Harris’ 16th novel featuring Sebastian, but it is easily accessible to anyone new to the series. While a subplot deals with Sebastian’s family lineage, the novel mostly follows a procedural course, building suspense and dread as Sebastian questions the victim’s acquaintances and possible enemies. Harris guides us through London’s streets with detail and dialects that firmly establish the novel’s immersive historical setting. In her afterword, Harris recounts which elements of the novel she drew from actual depositions, testimonies and newspaper reports.

Whether your passion lies with a detective’s meticulous pursuit of evidence or you thrill to the hunt for a killer, these books deliver on both accounts.