Mystery has surrounded the death of a woman who died at the bottom of a staircase in her own home, with lawyers convinced an owl killed her.
Kathleen Peterson was a businesswoman and philanthropist who lived with her writer husband Michael in Durham, North Carolina, and died in mysterious circumstances in 2001.
Her death has been the subject of documentaries, books, TV shows and podcasts ever since as has been described as the the most captivating real life true crime story you've never heard of.
On Thursday, a mini-series called The Staircase and featuring Oscar-winning actor Colin Firth as Michael Peterson, is due to premiere on Sky Atlantic.
Husband Michael has always claimed his wife tragically fell to her death, but he was later found guilty by a jury of her murder.
The court heard he brutally attacked his wife with a blow poke from the open fire, causing 35 injuries including a number on the back of her head, leaving her in a pool of blood at the bottom of the stairs.
He made a harrowing call to police saying his wife was still alive after falling down the stairs, but when officers arrived her body was cold and her blood had congealed.
The prosecution argued his motive for killing his wife was that she had found out he was using male escorts and she had a $1.5million (£1.1m) life insurance policy with her husband as the beneficiary.
Mr Peterson always denied he attacked his wife and did not take the stand during his trial.
He was sentenced to life in prison.
He also denied being involved in the death of the Peterson's family friend Elizabeth Ratcliff who was found dead at the bottom of a staircase in 1985, despite being the last person to see her alive.
Following Michael's conviction for murder his lawyers launched an appeal, and even had an alternative theory of who killed Kathleen - an owl.
The Owl Theory was first mooted by the Peterson's next-door neighbour and lawyer, Larry Pollard who claims all the evidence points to Kathleen being attacked by a predatory bird.
Mr Pollard theorised that 48-year-old Kathleen was 'slammed' by an owl by the family's swimming pool as she put out animal ornaments for Christmas.
He says she ripped out her own hair as she tried to get the bird off her head, rushed into the house in a bid to escape the attack and fell as she tried to climb the stairs.
He says the wounds on her head look like they were created by an owl's talons, Kathleen's own hair was found in her hands, a microscopic feather was found on her body, and owl's were known to live in the neighbourhood in Durham.
Mr Pollard told the Beyond Reasonable Doubt podcast in 2017 that he has no axe to grind in the case and simply wanted to get to the truth.
He added that the only way to finally find out what happened is to exhume Kathleen's body and carry out an MRI scan of her head to show if there were fissures from an owl's talons or crushed bones from an attack with a blow poke.
He told the BBC podcast: "That is the challenge that I say is there, that is where the rubber meets the road and where the talon meets the skull."
Arguments against the owl theory were that Michael was at the home at the time, and would have heard his wife screaming as she ran into the house from the owl attack.
Speaking about the owl theory Michael Peterson himself said: "I do know that the owl is every bit as realistic as that ridiculous blow poke thing."
And his lawyer David Rudolph added: "When I first heard it, I thought it was ridiculous."
After serving eight years in prison, Michael was freed pending a retrial.
But the owl theory was never tested by a jury, as while out on appeal, he went to court and instead of a retrial he pleaded guilty to killing Kathleen by involuntary manslaughter as part of an 'Alford plea' in 2017.
The Alford plea meant that Michael agreed the prosecution had enough evidence to convict him of killing his wife.
Having already spent time in prison before his appeal, Michael Peterson walked free from court in 2017.
He still denies attacking his wife.
