The Tunnel By Carl-Johan Vallgren. Translated by Rachel Willson-Broyles. (Quercus, 336 pp. $26.99)

Holy Ceremony By Harri Nykänen. Translated by Kristian London. (Bitter Lemon Press, 252 pp. $14.95)

Swedish author Carl-Johan Vallgren’s ingeniously plotted The Tunnel is gritty and gruesome. It features private investigator Danny Katz—ex-military intelligence, computer and language expert and former heroin addict.

When Katz discovers that his friend and one-time drug dealer, Ramon, has been murdered and the police have dismissed his death as just another junkie overdose, Katz decides to pursue the case independently. After all, Ramon had once saved Katz’s life when he OD’d.

This chilling novel takes place in Stockholm’s netherworld, where pedophiles and sex and drug traffickers live, their crimes protected by the authorities. Katz is tough and doesn’t take guff from anybody, especially anti-Semites. There are subplots involving two of Katz’s friends, one of whom is involved in an armed robbery; the other, also a former drug addict, is now a prosecutor and single mom.

These storylines and their resolutions skillfully merge in an exciting denouement. There is also a plot twist that will make readers want to catch up with Vallgren’s first, recently reprinted, Danny Katz murder mystery, The Boy in the Shadows.

Holy Ceremony by Harri Nykänen features Ariel Kafka, one of only two Jewish cops in Helsinki and a lieutenant in the city’s Violent Crimes Unit. He’s based in part on Dennis Pasterstein, a real-life lieutenant in the same Helsinki police department unit.

Holy Ceremony begins with the police discovery of Roosa Nevala’s body. Roosa, who apparently committed suicide, has biblical references carved on her body. The police also find a letter beneath her body addressed to Kafka by The Adorner of the Sacred Vault, promising more bodies.

The mystery deepens when Roosa’s body is stolen from the morgue and found burnt. Soon, other bodies begin piling up. It appears that a high school cult is to blame—but then again, maybe not.

I found Kafka to be the book’s main draw: He is an intelligent and respected cop who nevertheless experiences anti-Semitism. When investigating a colleague for accepting bribes, he is told: “If I were you, as a kike, I wouldn’t talk about taking anyone to the cleaners.”

It was the first time a colleague had called him that slur, and to Kafka “it felt like I was slapped across the face.”

Kafka’s casual relationship to Judaism adds color and sympathy, as he attends his brother’s family seder and belongs to the local Jewish community center.

I found Holy Ceremony so extraordinary that I went back to read Nykänen’s two earlier Ariel Kafka mysteries, Nights of Awe and Behind God’s Back. They are equally excellent.

Curt Schleier, a freelance writer, teaches business writing to corporate executives.