Strange, rhymed advertisements in the TIMES unsettle three London gangsters - and rightly so, because soon the first of them are killed. The mysterious killer also catches a shady lawyer. Higgins and Lane find out that the key to the crimes is an unsolved diamond heist from jeweler Bolden. It looks like those involved are fighting over the loot. Eventually, it turns out that the "robbery" was actually a set-up insurance scam that Bolden was personally behind and that killed his employee. Shortly before the last survivor is sent to the afterlife, Higgins and Lane are able to confront the "invisible" murderer.
Unfortunately the movie Die unheimlichen Briefe is not yet available on HBO Max.
| Writing | Florian Pauer | Writer |
| Writing | Peter Jürgensmeier | Writer |
| Directing | Wolfgang F. Henschel | Director |
| Production | Angela Marquis | Casting |
| Costume & Make-Up | Hasso von Hugo | Makeup Artist |
| Directing | Claudia Beewen | First Assistant Director |
| Sound | Andreas Walther | Sound |
| Lighting | Dietmar Haupt | Gaffer |
| Sound | Stephen Keusch | Music |
| Camera | David Slama | Director of Photography |
| Camera | Dariusz Brunzel | First Assistant Camera |
| Lighting | Ralf Prokopp | Electrician |
| Production | Horst Wendlandt | Producer |
| Costume & Make-Up | Annett Schulze | Makeup Artist |
| Art | Wolfgang Roeder | Set Decoration |
| Visual Effects | Michael Bouterweck | Special Effects Supervisor |
| Camera | Glenn König | Assistant Grip |
| Costume & Make-Up | Nina Büttner | Wardrobe Master |
| Production | Alexander Binder | Production Driver |
| Production | Norbert Mentrop | Production Driver |
| Lighting | Marco Teuchert | Electrician |
| Production | Maike Creteau | Production Secretary |
| Art | Marcus Berndt | Property Master |
| Costume & Make-Up | Uli Simon | Assistant Costume Designer |
| Crew | Georg Armin Sauer | Stunt Coordinator |
| Editing | Sabine Brose | Editor |
| Costume & Make-Up | Anette Tirler | Wardrobe Master |
