Sadie Hartley murder: What drove a woman to kill her love rival?
Sarah Williams has been found guilty of stabbing to death her love rival. But what led the 35-year-old to murder Sadie Hartley?
On a cold evening just days into 2016, businesswoman Sadie Hartley returned home after tending her horse.
A short time later, she was dead - shot with a 500,000-volt stun gun and stabbed 41 times by love rival Sarah Williams, a ski instructor.
Ms Hartley was found by police the following night, 15 January, face down in a pool of blood following an act described in Preston Crown Court as "uncontrolled butchery".
The 60-year-old medical communications director and her partner Ian Johnston, 57, had shared a £500,000 home in the Lancashire mill town of Helmshore since 2014.
They had been in a relationship, at times intermittently, since 2005.
But in 2011 Mr Johnston, an ex-fireman, met Williams, now 35, at the indoor ski slope of Manchester's Chill Factore, where they were both working.
She was more than 20 years younger than him but, two years later, they had embarked on a sexual relationship.
Williams confided in a text message to a friend that the "fireman is just totally awesome... I'm hook, line and sinker".
She wrote in another text message: "The fireman has feelings for the golden haired, brilliantly creative and creatively brilliant She Devil."
She added: "I'm screaming at a pitch where only dogs and bats can hear me."
The relationship would become a fatal obsession for Williams, who wanted to continue the affair even when Mr Johnston tried to dump her some months later.
But when he went on a skiing holiday with Ms Hartley he continued flirting with Williams, who was staying at the same hotel.
She was there with her married lover David Hardwick - labelled in court as a "sugar daddy" - with whom she had been in a relationship since she was 17 and he was 57.
Now aged 75, the semi-retired businessman said he had "no idea" Williams had been having an affair with Mr Johnston.
Mr Hardwick admitted he paid for up to 12 holidays a year - for himself and Williams - in addition to giving her £75,000 towards buying a house and paying £320 a week into her bank account by standing order.
Williams told the jury her relationship with Mr Johnston had "basically broken down" in 2014 but she remained obsessed with him.
In September that year she sent an anonymous letter to Ms Hartley, boasting she had had "fantastic" sex with Mr Johnston and accusing her of blackmailing him to stay together.
Williams admitted in court "it was a crap thing to do".
Mr Johnston told the jury: "Sadie asked me who it was from and I said it was Sarah Williams."
The two women had a phone conversation afterwards, with Williams telling the court Ms Hartley did not ask her why she had written the letter but did ask if she lived nearby.
Williams admitted in court it was not the first time she had sent a "vengeful" letter in jealousy.
Some years earlier, she had a relationship with Somapat Sitiwitjana, a married Thai martial arts and ski instructor, known as Master A.
The court heard his wife found out about the affair when Williams visited her home in May 2012 and when, two weeks later, she sent a letter saying "I think you should know about the sort of scumbag you are married to..."
In the note, she claimed she was pregnant by him - although she was not - and included a baby scan image, admitting in court it was actually that of a friend's baby.
In 2014, following a short break in their relationship, Ms Hartley and Mr Johnston decided to move in together to a new home in Helmshore.
Williams continued to send Mr Johnston messages, which he did not block. In December 2015 they exchanged explicit texts that carried on into the new year, when he was in Switzerland.
Ms Hartley had been due to join him there for a skiing break but never made it.
Her murder on 14 January had been planned by Williams and her friend Katrina Walsh, who worked as a horse-riding instructor.
Described in court as "well-educated, extremely intelligent, eccentric", Walsh chose not to give evidence during the trial.
The 56-year-old earlier told police she never believed Williams would carry out the crime and that she thought they were playing a game inspired by Hunted - the Channel 4 show where people try to avoid detection by "going off-grid".
The friends visited Germany before Christmas and bought the 500,000-volt stun gun. The saleswoman recalled Williams wanted to buy a device capable of firing one million volts before finding out it was not in stock.
Who is Katrina Walsh?
As a horse riding instructor, Katrina Walsh first met Sarah Williams at stables when the latter was aged 12.
Known as Kitt, she married Kevin Walsh in 1984 but he left her for another woman in 2008.
Walsh, 56, who suffered from alopecia, was in a biker group, used Tarot cards and would make dragon-themed pendants.
She bought the car and the tracker used in the murder plot, along with the knife and some of the clothing Williams would wear.
After their arrests, the pair, who had an age gap of 20 years, fell out and did not acknowledge each other in court - Walsh barely lifting her head while Williams made notes.
Walsh's copious diary entries recorded the plan to kill Sadie Hartley, with the former riding instructor noting she had "no moral qualms".
Ten days before the murder, Williams sent Walsh a text that read: "Don't forget to crack on with your shopping... suddenly it's time."
The next day Walsh bought the knife used in the murder with her Tesco Clubcard.
A week before the murder, the friends went on a daring "dry run" to scout out Ms Hartley's home.
Walsh delivered a bunch of chrysanthemums directly to Ms Hartley at her door, while Williams watched from a distance.
On 14 January, the latter drove alone at night to the Helmshore residence. A neighbour's CCTV camera showed Williams parking up at the end of the road, leaving her car and then - four minutes later - calmly returning.
In that short time, Ms Hartley had answered the door to Williams who then fired the stun gun and stabbed her 41 times.
Senior investigating officer Paul Withers, from Lancashire Police, called it a "frenzied attack" and said: "Sadly Sadie suffered absolutely appalling injuries and, I would suggest, very quickly lost her fight for life".
Throughout the case both Williams and Walsh denied murder, with the former claiming she was asleep at her Chester home when Ms Hartley was killed.
But CCTV footage showed her driving after the attack to a car park in Ellesmere Port, Cheshire, where she met Walsh who then drove her home in a separate car.
Walsh tried to destroy her friend's blood-stained clothes and boots, and hide them at a farm. After her arrest, she took investigating officers to the area where they found the stun gun, knife and incriminating diary entries.
Police also found Ms Hartley's DNA on Williams's bath and spectacles.
Williams and Walsh were described in court as former friends who had "fallen out now and blame each other".
Even Walsh's defence barrister described the pair as "vile" and "guilty as sin".
Mr Johnston has since said: "I've been a fool, I was unwitting", adding he did not think his relationship with Williams would lead to "such a savage, horrible murder".
"If [Sadie's family] feel that I was contributing, I apologise wholeheartedly. I can never, ever, come to terms with that."