SINFULLY GOOD

When a young mother carries out a brutal and apparently senseless murder, a detective with secrets of his own is determined to uncover her motive, in riveting thriller The Sinner

Families and sunbathers are enjoying a beautiful summer’s day on a beach by a lake when the blissful peace is shattered by an act of quite extraordinary savagery.

Young mum Cora Tannetti is using a knife to peel a pear for her young son Laine when she suddenly stops and launches into a frenzied attack on a man sitting nearby. Frankie Belmont, a 29-year- old doctor who had been embracing his wife, is stabbed multiple times and dies of his injuries. Dozens of witnesses beside the lake, in upstate New York, see the ghastly attack and the desperate attempt by Cora’s husband Mason to drag her off Frankie.

Cora is arrested and readily confesses to the killing when interviewed by detectives Dan Leroy and Harry Ambrose. Dan is satisfied it’s an open-and-shut case, but Harry, played by Hollywood star Bill Pullman, is baffled and wants to know what drove her to commit such a heinous crime.

The Sinner, an Emmy and Golden Globe-nominated eight-part thriller, follows Harry’s investigation as he sets out to explain the motive behind the seemingly senseless attack. The series first transfixed viewers on Netflix, but now begins tonight on BBC4 with the first two episodes.

‘The show reveals the truth, but viewers will have to be patient,’ says Jessica Biel, the US actress, married to pop star Justin Timberlake, who plays Cora. ‘Over the course of each episode a couple of clues emerge as to why my character did what she did, and by the end of the final episode the explanation is complete.’

Cora’s attack doesn’t come entirely out of the blue. Earlier she has upset Mason by swimming out into the lake, too far for his liking. Then, back on the beach, she is irritated by the loud music being played by Frankie and his partner Leah and by their intimacy. ‘Get off her,’ she cries, as she runs towards him knife in hand.

More cryptic clues emerge in the aftermath of the killing – there are flashbacks to Cora’s childhood, when her sister Phoebe was desperately ill and their deeply religious mother believed that only total devotion to God would ensure her survival. ‘Everything he expects of us, we must do,’

she tells the four-year-old Cora. ‘It’s the only way your sister will live.’

Intricate details of the fatal assault which weren’t at first apparent are also revealed. Cora denies knowing her victim yet, when interviewed by Detective Ambrose, Frankie’s friend Patrick says that he grabbed her by the arm after suffering the first blow and could have easily fended her off, but appeared to recognise Cora and let her carry on stabbing him. Also, Cora’s husband reports that after the attack Cora told Frankie’s partner, ‘You’re safe – he’s gone now.’

‘ It’s a labyr inthine case that becomes more and more complicated the more it’s investigated,’ explains Bil l Pullman. ‘ It makes sense. There’s never going to be an easy answer to say why somebody can commit something as complicated as

murder when they appear to have no serious inclination to do so.’

The Sinner is based on a bestselling 1999 German novel of the same name by Petra Hammesfahr, with the action transferred from Germany to the fictional US town of Dorchester.

Jessica Biel wanted to appear in the TV adaptation after becoming enthralled by the book. ‘Every twist and turn was so unexpected,’ she says. ‘I reckon I’m a bit of a savvy reader, and I was thinking, “OK, I know where this going, it’s probably going to land over here,” and each time I was wrong.

‘That was why I had to do it, why I had to be Cora, because it was completely blowing my mind. I think it will have a similar intriguing and disorientating effect on viewers.’ The Sinner, tonight, 9pm, BBC4.