Professor T investigates a ritual double murder.

Professor T discovers similarities to his own painful childhood while searching for a family’s missing son.

After a brewery owner is found dead, Professor T learns every member of the victim’s family had a motive for murder.

Chief Inspector Rabe is the prime suspect in a double murder, and only Professor T can help him.

Professor T investigates a seemingly perfect murder.

Professor T unravels a mystery after a plastic surgeon is found murdered in his hotel room.

Professor T returns to Cologne to help Daniel track down a killer.

A husband returns home to a grisly scene, and only Professor T can solve the brutal crime.

Professor T investigates when a nuclear physics student collapses dead in his office.

Professor T consults on a campus rape case, identical to a decade-old incident in the same dorm.

Professor T is implicated in the killing of a high-class call girl.

Professor T investigates a gossip columnist's murder.

Daniel's fiance's boss is murdered, but Professor T is indisposed.

Professor T attempts to solve a crime close to home.

Professor T's latest case coincides with his wish to resume a normal life.

Professor T attempts to solve the case of a murdered Neo-Nazi.