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 Disney Plus.
| Directing | Wolfgang F. Henschel | Director |
| Writing | Peter Jürgensmeier | Writer |
| Writing | Florian Pauer | Writer |
| Production | Horst Wendlandt | Producer |
| Sound | Stephen Keusch | Music |
| Camera | David Slama | Director of Photography |
| Editing | Sabine Brose | Editor |
| Production | Angela Marquis | Casting |
| Art | Wolfgang Roeder | Set Decoration |
| Costume & Make-Up | Annett Schulze | Makeup Artist |
| Costume & Make-Up | Hasso von Hugo | Makeup Artist |
| Directing | Claudia Beewen | First Assistant Director |
| Art | Marcus Berndt | Property Master |
| Sound | Andreas Walther | Sound |
| Visual Effects | Michael Bouterweck | Special Effects Supervisor |
| Crew | Georg Armin Sauer | Stunt Coordinator |
| Camera | Dariusz Brunzel | First Assistant Camera |
| Lighting | Dietmar Haupt | Gaffer |
| Camera | Glenn König | Assistant Grip |
| Lighting | Marco Teuchert | Electrician |
| Lighting | Ralf Prokopp | Electrician |
| Costume & Make-Up | Nina Büttner | Wardrobe Master |
| Costume & Make-Up | Anette Tirler | Wardrobe Master |
| Costume & Make-Up | Uli Simon | Assistant Costume Designer |
| Production | Alexander Binder | Production Driver |
| Production | Norbert Mentrop | Production Driver |
| Production | Maike Creteau | Production Secretary |
