Grabenplatz 17 (1958)

In Hanover, a boy named Michael Peters finds his strangled mother, the prostitute Ella Peters, and then disappears without a trace. Detective Chief Inspector Dr. Jäger and his assistant Willy Wagenknecht find evidence of a stolen transmitter and a sailor’s cap in the murdered woman’s apartment. The investigators initially suspect the woman’s divorced husband, boatswain Jan Peters. Soon afterward, Dr. Bühler tells the officers that the missing Michael has leukemia and has only a week to live without medical treatment. The detectives locate an aunt the boy had planned to stay with. When he found she wasn’t home, he left a note saying he was on his way to Hamburg to see his father. A red-haired woman claiming to be a police officer then came and collected the note. Jan Peters, whom they have since tracked down, has a solid alibi for the time of the crime. He suspects his son may be staying in Hamburg with the mother of his girlfriend. Before Inspector Jäger can get there, the terminally ill child is abducted by the supposed policewoman and a man driving a blue Mercedes. That same evening, Jäger and Wagenknecht see a driver in a car of that kind and memorize the license plate. The following morning, they discover that the car has been reported stolen by business tycoon Harald Flint. Fingerprints found in the Mercedes, which has since been discovered abandoned, quickly lead the officers to the identity of the man they are looking for. He is Eugen Machon, a bookmaker with prior convictions for theft and fraud. Inspector Jäger and his assistant Wagenknecht pay Flint a visit. The widowed father of a young daughter says he knows Machon from various horse races. A race is taking place that very day. But before the police can catch Machon there, he is murdered in the crowd. The boy’s abductor is forced by Machon’s killer, the burly Titu Goritsch, to hide Michael somewhere else. At least the officers find a note in Machon’s apartment, written in the hand of the suspected mastermind. Out of pity for the terminally ill child, whose condition is getting worse, the red-haired woman finally identifies herself to Inspector Jäger as Isabella, a singer. She is expecting him the following evening at the nightclub “Black Spider” to reveal where the boy is hidden. Goritsch, who is also at the disreputable dive, recognizes the investigators at once. He promptly has Isabella abducted and taken with Michael to another apartment. At the “Black Spider,” Jäger runs into Harald Flint, who claims to own the dubious nightclub. The inspector is astonished when he happens to see that Flint’s handwriting matches the writing on the note from Machon’s apartment. After a fierce brawl and a clever attempt to escape, the police arrest the unscrupulous businessman. At Flint’s villa, Jäger and Wagenknecht even discover a motive for Ella Peters’s murder. Flint had hidden a transmitter in a hat and used it during horse races to relay the likely winner to a front man, who could then bet on that horse. When Ella Peters wanted to get out of the scheme, she was murdered, and her son Michael was abducted as a potential witness. Although Flint has a young daughter of his own, he vehemently denies the accusations and refuses to reveal where the terminally ill Michael is being held. Jäger sees only one chance to save the boy: to find the hiding place using a new invention by Wagenknecht’s uncle, a renowned police chemist. The officers coat Flint’s shoes with radioactive paint and stage an opportunity for the suspect to escape, which he takes. An exciting chase with a Geiger counter begins. The trail leads to Grabenplatz 17, where Flint, Isabella, and the sick boy are. At the last moment, Flint calls his daughter to say goodbye. Then the police officers shoot him.