In his 2010 true-crime memoir, In With the Devil (co-written with Hillel Levin), James Keene tells the story of how he went undercover in a federal prison to help take down a suspected serial killer. The Chicago native was at a Michigan federal prison, in the middle of serving a 10-year sentence for drug dealing, when assistant U.S. attorney Larry Beaumont approached him with an unusual proposal: He would transfer Keene to the U.S. Medical Center for Federal Prisoners in Springfield, Missouri, in order to ingratiate himself with Larry DeWayne Hall, then serving a life sentence for kidnapping and killing teenager Jessica Roach. Beaumont suspected that Hall was responsible for up to 20 more killings, and he wanted Keene to elicit a confession—and if he could get Hall to give him the specific location of another victim’s body, it would mean a get-out-of-jail-free card for Keene. Reluctantly, Keene agrees to do it, and the book chronicles his attempts to earn the confidence of a convicted murderer, as well as Keene’s and Hall’s backstories and the investigation that eventually landed Hall in prison.

It’s a by-the-numbers true-crime tale, heavy on dry reportage and low on atmosphere. A new Apple TV+ miniseries adaptation, Black Bird, which stars Rocketman’s Taron Egerton as Keene and Cruella’s Paul Walter Hauser as Hall, attempts to accentuate the darkness of the story, with mixed results.

Black Bird is certainly a better title—a reference to the small wooden falcons that Hall whittled in wood shop. In With the Devil implies that Hall is some kind of demonic presence, but he emphatically is not; as depicted in the book and miniseries, he’s just a weird creep. The fact that the crimes he’s accused of are monstrous doesn’t make him some kind of supervillain; instead, he’s depicted as a deeply odd, socially awkward guy who tinkered with cars and grew massive muttonchops to fit in better while taking part in Civil War re-enactments. (This odd choice of facial hair made it into the miniseries adaptation, although, in real life, Hall had shaved off the beard by the time Keene met him.)

The 2017 Netflix series Mindhunter—which was loosely based on a 1995 nonfiction book by John Douglas and Mark Olshaker—understood the banality at the heart of serial killers’ evil; imprisoned murderers initially seem perfectly ordinary and reasonable, and then they calmly and matter-of-factly describe their horrific crimes to investigators. It’s the low-key way they do so, with no flashy flashback sequences, that makes the confessions so terribly chilling. The best parts of Black Bird attempt to replicate Mindhunter’s tone, focusing on Hauser’s committed portrayal of Hall as a calm, soft-spoken presence; he’s upsetting, but in a subtle way, and he’s never a melodramatic, Hannibal Lecter-style monster.

The scenes in the prison also have an effectively moody and claustrophobic feel. However, the audience never feels trapped there with Keene, which undermines the narrative tension; instead, the miniseries features long sequences recounting the investigation into Hall’s alleged crimes, with Greg Kinnear as a vigilant small-town sheriff. These are diverting scenes, and Kinnear gives an engaging performance, but the cop’s repeated drives by sunny cornfields feel tonally jarring, and the whole subplot feels irrelevant and unnecessary in the end. Unfortunately, so does the presence of Keene’s ex-cop father, Big Jim, played with authority by Ray Liotta in one of his final roles.

Egerton does fine work as Keene, convincingly portraying a preternaturally charming guy who can ingratiate himself with anyone—even someone who may have killed dozens of teenagers. Keene comes off as a somewhat flawed character, though; after all, he was an admitted drug dealer, working with a Mexican drug lord and other gangsters, and he only took on his undercover mission to get out of jail, not because of any moral imperative to get justice for young murder victims. Despite this, Keene seems almost superheroic in the memoir; he gets into several fights—with an abusive stepfather, with hardened criminals—and wins, and he effortlessly charms fellow prisoner and Mafia boss Vincent “the Chin” Gigante, who treats him almost like a son. One never thinks for a minute that Keene will ever be in real danger or have any difficulty getting Hall to tell him anything he wants.

It’s a key problem, and it’s one that transfers to the miniseries, which was developed and co-written by novelist Dennis Lehane. The creators seem to sense the lack of suspense, as they add brand-new conflicts and confrontations to help remedy it, but these additions frequently lead nowhere. The miniseries is worth seeing for Hauser’s performance alone; an Emmy win certainly wouldn’t be a surprise. But those expecting a tense horror-thriller would do best to simply watch Mindhunter again.

David Rapp is the senior Indie editor.