Set in Los Angeles in 1942, the latest instalment in James Ellroy’s occult saga of US history centres on Irish-born police sergeant Dudley Smith, a closet Nazi using his rank as a front for activities including drug running and people trafficking.

In his day job, he’s coordinating a manhunt for a blood-drinking necrophile, Tommy Glennon, though Smith’s real reason for wanting to find him isn’t the obvious one, having more to do with Glennon witnessing what Smith once got up to at a Nazi orgy in the company of Orson Welles.

Sent to tail Glennon, Elmer Jackson (another Ellroy regular, drawn from a real-life detective) unearths little but an address book full of cryptic leads that the rest of the novel spends pursuing. By the time Glennon resurfaces some 400 pages later, he’s been all but drowned out by the intervening litany of sextortion rackets, punishment beatings and other grisly incidents, including the murder of a Chinese restaurateur found fried to death on his own hob.

Life here is breathtakingly cheap. When Smith’s double-crossing love interest, Joan (seen in 2014’s Perfidia), drunkenly crashes into a car, the investigating officer can pull strings because her victims are Mexicans with criminal records; she’s never told that two children, in the boot of the vehicle she hit, also died.

Such moments aren’t milked for pathos; far from it. When Jackson interviews the widows of two murdered colleagues, Rice and Kapek, we’re asked: “You want baleful bile? Gas on this: Rice pimped his wife to cover his poker debts. Rice fathered Kapek’s three kids, and vice versa. The widows were lezbo lovers... Rice and Kapek filmed their antics [and] made them wear dirndl skirts and Nazi armbands…”

In Ellroy’s crunchy, slang-studded staccato, characters don’t curse but “hex”; they “orb” things rather than look at them; someone undertakes “perfunctory woof-woof in the missionary manner”. One corrupt cop is introduced by telling us he “speaks Chinese and drills underage slash”; a prostitute, we’re told, has “green eyes. She ran 5’10”/150. She induced loooooooow growls.”

This Storm isn’t a police procedural – it’s too sprawling for that – but interrogation is the basis of its narrative engine, with fog-clearing info-dumps delivered during grimly inventive torture scenes. The frequent bed-hopping does the same job: you suspect Ellroy sees the funny side when Jackson’s lover says: “You came here to pump me... And I’m not talking about in the sack.”

Often, the novel reads like the result of a hyper-caffeinated storyboarding session, with characters that seem to matter less than the cynical, conspiratorial world they represent. It hardly helps that the vast cast is full of aliases and near-homophones, including a José Vasquez-Cruz who “was really Jorge Villareal-Caiz”, and a serial killer known as the Werewolf, who pops up alongside the Wolf, a separate, spectral apparition.

Relentless and disorienting it may be, but Ellroy has never been a five-pages-before-bed kind of writer; his vision is more the fever dream after lights out.

• This Storm by James Ellroy is published by William Heinemann (£20). To order a copy go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99