The Investigation is a Scandi police procedural that centres its real-life victim

▶ Six episodes of The Investigation are available on iPlayer.

A sombre, sober outing in TV’s most lurid genre, this true-crime drama about the Danish ‘Submarine Case’ of 2017 wears its ethical stance proudly. Writer-director Tobias Lindholm’s six-part series about the murder of journalist Kim Wall in a midget submarine belonging to a Copenhagen inventor deliberately concentrates on the police rather than the perpetrator: refusing to namecheck, let alone show the killer (he’s referred to throughout as ‘the accused’), it’s in sharp contrast to recent series like ITV’s Des, about Dennis Nilsen, or the BBC’s The Serpent, about Charles Sobhraj – dramas visibly fascinated by the sang-froid or charisma of their infamous subjects.

A determinedly low-key, naturalistic, and compassionate procedural, it tracks the case from the point of view of the dogged head of homicide Jens Moller (a preternaturally calm Soren Malling). Like the heroes of Lindstrom’s films A Hijacking (2012) and A War (2015), he’s a profoundly decent man, battling the toughest of circumstances. As a howdunnit, rather than a whodunnit, The Investigation follows his painstaking casework minutely, from Wall’s reported disappearance through the nightmare job of finding the victim’s remains, scattered somewhere in the depths of the vast Koge Bay.

Shaped as a series of challenges – getting the sub raised, struggling to find physical evidence, the killer’s interview stories shapeshifting through successive grisly fabrications – its scenes are datestamped, underlining the endlessly frustrating months of legwork it takes to build a case in real life. That said, the list of generic motives (“Lust, Power, Revenge, Jealousy, etc”) that Moller insists on talking through on the unit’s whiteboard feels dropped in purely for viewer elucidation, oddly in a show that prides itself on its relentless realism. Lacking the lures of grandstanding performances, chase sequences, or emotional spectacle, the series needs you to lean in and commit to its measured pace and the case’s slow progress. All of it comes wrapped in Scandi-noir blue-grey visuals and a pervasive melancholy, as Moller and his crew chafe, stare and wait for inconclusive pathology reports and fruitless diving expeditions.

In the absence of the killer figure, the sea becomes the unit’s visible foe. Lindholm’s script is fascinating about the difficulties of finding human remains at sea without exact coordinates, a grizzled navy commander comparing it to seeking a pin on an underwater football field with one eye closed. As the Danish police slowly piece together, over two episodes, how to find Wall’s remains using Swedish ‘cadaver dogs’ and an oceanographer’s knowledge of the shifting currents, you marvel at their ingenuity. But without explosive interrogation scenes or tense courtroom takedowns, the diver’s gradual successes, vital to proving the cause of death, are the show’s sole ‘show not tell’ sequences.

On land, the show’s decision to keep the killer off-camera means that everything the police pore over is reported second-hand, from his unseen interviews, his friends, or his laptop – his taste for snuff movies, his obsession with ‘the perfect crime’, his cunningly misleading accounts of Wall’s death. As the case winds on, you realise that Lindholm’s careful storytelling is, in a way that’s new to the genre, working hard to be responsible to the facts and respectful to the Wall family.

The show’s refusal to fetishise the killer forces the viewer to consider how we routinely consume real-life tragedy in dramatisations, as an access-all-areas spectacle. Here we never see a single retrieved body part, Lindholm preferring to represent Wall as a journalist who died while working on a story rather than the mutilated victim of a predatory psychopath. This delicacy is mirrored in the show’s cinematography, the camera often keeping a respectful distance – lingering by the gate as the Wall parents are notified of Kim’s death in longshot, or watching Moller through a window as he cogitates. Rune Tonsgard Sorenson’s music soundtrack is similarly restrained, employing its thudding cello strokes only for key revelations.

What grabs and holds you through the long trek to justice are some fine performances, particularly the dignity of Ingrid and Joachim Walls, played impeccably by Bergman veteran Pernilla August, and one-time Wallander Rolf Lassgard. If Pilou Asbaek’s public prosecutor Jakob often feels like a device explaining the exacting demands of the ‘burden of proof’, Malling’s quiet but persistent Moller is a subtle portrayal, full of grace notes, like his blurted “I wish you’d never met me,” as Ingrid Wall hugs him goodbye. Dogged by a tabloid journalist’s calls, he’s appalled by the public’s obsession with murder, despite Denmark’s lowest-ever homicide levels – about 50 deaths annually. Jakob’s answer to him speaks to our own true-crime cravings and the show’s internal dilemma: “Maybe it’s because as we get more civilised, the greater grows our need to stare into darkness.”