In its final episode Undercover tied up a lot of loose ends and introduced a number of new ones. The biggest loose end to remain unaddressed was pretty big. Nick Johnson was the alias of a policeman who in 1996 went undercover to spy on black activist Michael Antwi and his lawyer Maya Cobbina. Nick promptly fell in love with Maya; they married and had children.

The BBC Drama department can’t be faulted for reading the news. Last year London Spy riffed on the mystery of the corpse of the spy found in a suitcase in an MI6 safehouse. Now Undercover sinks its teeth into another juicy set of headlines about coppers who go into such deep cover they sire children with the activists they’re spying on.

The opening scene of Ramin Bahrani’s 99 Homes plunges us into the darker depths of American society, post-2008 financial crisis. We’re in the world of home repossessions, and the blood spattered around the bathroom of one property by an ex-owner who wouldn’t go quietly speaks chillingly for what is in store.

Finally the moment the Breaking Bad diaspora has been waiting for, with the arrival of Vince Gilligan's new show about the earlier career of New Mexico's least scrupulous lawyer, Saul Goodman. Mind you, the title is a little bit misleading, because Saul doesn't exist yet. In this incarnation, he's still just a hustling low-life called Jimmy McGill, a man who never knowingly leaves any barrel unscraped.

Four years ago Christopher Jefferies was the victim of a concerted attack by the British press. His tenant Joanna Yeates had been murdered and, lacking any other leads, police arrested her landlord. While he was still being questioned, the newspapers sniffed around Jefferies’s patch of Bristol and, armed with a juicy quotation or two, chose collectively to forget all about the principle of innocent until proven otherwise. "Weird", "posh", "lewd", "creepy" were among the epithets in The Sun. He was branded a peeping Tom.

Two knotted horrors stained West Memphis, Arkansas in 1993. Three 8-year-old boys, Stevie Branch, Christopher Byers and Michael Moore, went cycling on a sunny spring afternoon. Their torn, bruised and in Byers’ case castrated bodies were dragged from a stream the next day. Three local teenage boys, black-garbed outsiders Damien Echols, Jason Baldwin and Jessie Misskelley, Jr., were then tried for the crimes with a carelessness, incompetence and prejudice which seemed actively malicious. This “West Memphis Three” sacrificed 18 years in jail, as authorities who had in some cases risen to power on the back of the verdicts ensured they stood, despite an overwhelming weight of evidence against them. A rare and nonsensical Alford plea allowed the three’s release, unpardoned but maintaining their innocence, in 2011.

The Peter Jackson-produced West of Memphis (2012) has the highest UK profile of several documentaries which made the case a cause celebre. It was a campaigning film, highlighting how little innocence can count in US justice’s venal byways. This first dramatic account treads a quieter, more circumspect path. Director Atom Egoyan is fascinated with buried, often traumatic secrets. A hunt for a missing, murdered child is the horror behind the sexual sadness and pain of Exotica (1994), and the yellow school bus glimpsed early in Devil’s Knot recalls the town who lose a bus full of children beneath the ice in The Sweet Hereafter (1997). There was a fairy tale elegance and heartbreaking profundity to the latter film. Egoyan’s response to West Memphis’s loss is intentionally less certain and satisfying.

Reese Witherspoon is Pam Hobbs, mother of murdered Stevie, and Colin Firth is private investigator Ron Lax, pictured above right, who helped destroy the case against the West Memphis Three. Both give diligent, unstarry turns. Witherspoon’s Hobbs is a Southern Christian who tears locks of her hair out in grief, but comes to doubt the Satanic conspiracy the accused are believed to be part of in a conservative town bent on retribution. Firth slips under the skin of the quietly decent and angry Lax, a prosperous private eye helpless to directly effect West Memphis’s kangaroo court. They blend in with a strong cast including Alessandro Nivola as Terry Hobbs, pictured above left with Witherspoon, Pam’s watchful, faintly dangerous husband, and Egoyan regular Bruce Greenwood as Judge David Burnett, almost drumming his fingers with impatience to get to the guilty verdict.

The grisly comedy of the flagrantly biased courtroom makes the injustice clear. Egoyan, though, also humanises the staggeringly inept police by showing them wading through the stream, discovering and holding the boys’ corpses: the spark for a 21^st century trial compared here to Arthur Miller’s Salem.

Egoyan wants to leave us off-balance, turned around by contrasting perspectives, engaged by the mystery of the murdered boys’ fate, not the documentarians’ solution to the accused boys’ innocence. He isn’t helped by a script where characters explain themselves in Hollywood-style speeches, even as Hollywood’s satisfying resolutions are spurned. It’s a film I want to see again, in case the deeper mystery Egoyan aimed for is lurking in its murderous woods and human masks. But it feels as if he’s missed his subtle mark, veering between convention and understatement to underwhelming effect.

Overleaf: Watch the trailer for Devil's Knot