Two men who abducted, tortured and murdered missing businesswoman Lynda Spence have been sentenced to life in prison.

Colin Coats, 42, was jailed for a minimum of 33 years at the High Court in Glasgow, while his co-accused, Philip Wade, also 42, was ordered to spend at least 30 years behind bars.

The sentences are among the heaviest ever handed down in a Scottish court. The longest, of 35 years each, were imposed on Raymond Anderson and James McDonald for murdering Michael Lyons and trying to kill two other men at a Glasgow garage in 2006.

Trial judge Lord Pentland said Coats was the "prime mover" behind the 27-year-old's kidnapping and that he is convinced of his "devious and cruel personality".

David Parker, 38, and Paul Smith, 47, admitted holding Ms Spence at Parker's flat in West Kilbride, Ayrshire, in April 2011. They were sentenced to 11 years three months, and 11 years respectively.

The pair were charged with murder but their pleas of guilty to a reduced charge of detaining Ms Spence against her will, assaulting her and attempting to defeat the ends of justice were accepted by the Crown.

Lord Pentland said it was Parker and Smith's "despicable and cowardly" acts, by providing a place for Ms Spence to be held and guarding her for Coats and Wade, that contributed to what happened to her.

The judge described the crimes against Ms Spence as "truly monstrous and barbaric".

He said of Coats: "From the extensive evidence, I am left in no doubt you were the more dominant actor. You were the prime mover behind the abduction, torture and murder of Lynda Spence. I am convinced you have a devious and cruel personality.

"In my considered view, you are a ruthless and dangerous man."

As the sentences were heard in court, all four men stood with their heads bowed.

Gasps were heard from the packed public gallery as Wade was handed his 30-year jail term.

Ms Spence's parents, James and Patricia Spence, were at the hearing.

Coats and Wade, both 42, taped the 27-year-old financial adviser to a chair in a flat in Ayrshire in April 2011 and assaulted her every day for almost two weeks, then killed her.

A jury at the High Court in Glasgow found them guilty following an 11-week trial.

Coats and Wade forced Ms Spence into a car on Broomhill Path, Glasgow, on April 14 2011 and drove her to West Kilbride, Ayrshire, where David Parker and Paul Smith let them in to Parker's flat in Meadowfoot Road.

When she arrived, Ms Spence was wearing sunglasses which were taped on the inside, and Coats gripped on to her waist.

Wade carried in a tool bag which was referred to during the trial as "the torture kit", containing garden loppers, surgical tape and vinyl gloves.

They immediately whisked the woman upstairs to the attic area and taped her to a leather chair by the arms and waist.

In the days that followed, the two men would arrive every day to hurt her, as a way of trying to extract financial information. She was burned with an iron, hit with a golf club and they crushed her toes, cut off her thumb and severed her pinkie finger.

Parker told how he originally believed the arrangement was to help somebody that needed to get out of Glasgow, but as the situation "snowballed" he could see no way out of it.

He and Smith were also charged with Ms Spence's murder but were cleared after pleading guilty to a reduced charge of holding her against her will and assaulting her.

Ms Spence was not allowed to move from the chair for the 13 days she was there, and had to urinate and defecate where she sat.

On April 27 2011, Parker and Smith were dismissed by Coats and Wade, who told them: "Yous (sic) can go."

During the trial the court heard how Ms Spence and Coats were involved in a land deal at Stansted Airport, in which Coats claimed to have invested all of his money.

Wade was described as his "right-hand man" in the killing and later told a friend, Pamela Pearson, that he helped dispose of a woman's body.

In a statement, Ms Spence's parents, James and Patricia, said afterwards: "There is no verdict that will bring our daughter Lynda back or spare her the terrible ordeal that took her life.

"We will never begin to imagine her suffering or comprehend the cruelty of any person who would do that to another human being.

"We cannot begin to understand or forgive what they did to our daughter, Lynda. No words can begin to describe the heartache and pain we are suffering.

"We would like to give our sincere thanks to the solicitor general and her team for their dedication and bringing this case to a satisfactory outcome.

"We would also like to extend our thanks to Detective Superintendent Alan Buchanan and his team for their investigation in this case and to Petal (People Experiencing Trauma And Loss) for their valued support. All have been of great support throughout this ordeal.

"Lynda was a warm, kind and thoughtful daughter and was someone who always had time for others. We miss her so much."

Following the verdict, the officer in charge of the murder investigation, Detective Superintendent Alan Buchanan, said: "Police Scotland is pleased that the persons responsible for the abduction and horrific murder of Lynda Spence have been brought to justice.

"I hope in some small way this will bring some satisfaction to Lynda's parents who have had to endure the pain of hearing the graphic details of the horrific torture and terror inflicted on Lynda in her final days.

"Although satisfied with the verdict, the pain for the Spence family continues as due to the actions of the accused, Mr and Mrs Spence have been unable to lay their daughter to rest.

"At this time I would appeal for those convicted to show some common decency and tell us where Lynda is in order that we can get her back to her parents and allow them to grieve properly and move some way towards rebuilding their lives.

"The police cannot bring people like Coats, Wade, Smith and Parker to justice on their own and I would like to give a special mention to the witnesses in this case. Despite many of them being terrified of the accused, they had the courage to stand up and be counted to ensure that the people responsible for Lynda's abduction and murder pay for their actions."

The jury of six men and seven women took about 20 hours over five days to come to their verdicts.

They found Coats unanimously guilty of murdering Ms Spence, as well as disposing of her body, which has never been found.

Wade was also convicted of both charges, but he was cleared of cutting off the missing woman's head.

Coats, from Glasgow, was further found guilty of three other charges relating to his threatening behaviour towards John Glen and Patrick Burns to extort thousands of pounds from them, as well as stealing Mr Burns' car on May 18 2011 after Coats said he would stab him with a pen.

As the jury's verdicts were read out, Coats and Wade sat in the dock and made no sound. They were led back down to the cells with their heads bowed.

The packed public gallery, where some of the men's family members sat, was also silent.

Judge Lord Pentland said the court will sit again this afternoon when he will carry out necessary procedures.

In a bid to cover up the killing, Coats and Wade ordered a mass clean-up of Parker's flat.

It was scrubbed with bleach, while furniture, crockery and bedding was removed and floorboards and carpets ripped up and replaced.

The court heard evidence that the two men drove to Wade's friend's caravan in Tighnabruaich, Argyll, where they expressed a desire to "get rid of something".

Crown witness Lee Winyard said he believed the car they arrived in was the same as the one that featured in a missing person poster relating to Ms Spence's disappearance.

The silver Vauxhall Astra, which had a broken wing mirror, was hired for Ms Spence about two weeks before she vanished.

A phone used by Ms Spence was discovered in a bin outside the Lunchbox cafe in Kilbirnie, a North Ayrshire town about a mile from where Wade lived in Glengarnock.

Colin Coats and Philip Wade inflicted the most cruel and horrific catalogue of violence on Lynda Spence in her last days.

They hurt her over and over, smashing her knee caps with a golf club, chopping off her thumb, crushing her toes and burning her hands with an iron so badly that it left marks from the steam holes.

Ms Spence, 27, suffered the added humiliation of sitting in her own waste for at least 13 days having been taped to a leather chair with just a sweets tin under it to collect the mess.

She was forced into a car in Glasgow on April 14 2011 and driven to what would be her slow, painful death in a quiet residential street in West Kilbride, Ayrshire, where she was held captive.

Coats's motive was financial. He lost tens of thousands of pounds in a deal apparently dreamed up by Ms Spence, involving a land development next to Stansted Airport.

After being strung along by Ms Spence for the best part of a year, Coats's greed got the better of him. He lost face in the lie, along with all of his money, and he snapped, deciding upon a revenge attack that would bestow the most callous punishment upon the desperate woman.

He was in command with Philip Wade as his right-hand-man. Wade worked with Coats every step of the way, from Ms Spence's abduction in Broomhill Path to disposing of her body.

As she sat in that chair for the last two weeks of her life, Ms Spence never once called out for help. At one point she did ask David Parker and Paul Smith, who were offered money to guard her, if they thought Coats and Wade would ever let her go.

Ms Spence also spoke of feeling better after talking to her parents briefly during the ordeal, taking comfort in hearing their voices again.

Coats and Wade are believed to have decapitated the businesswoman and disposed of her remains. The question of where her body ended up is still unanswered.

The day after they killed her, April 29, Coats and Wade took Ms Spence's remains in the boot of her rented Vauxhall Astra to Tighnabruaich, Argyll, where they asked Wade's friend Lee Winyard if they could use his boat. He refused.

Coats later told a Peter Haddley, a cellmate at Addiewell prison in West Lothian, that they put her remains in a furnace. To cover up the crime, the two men ordered a mass clean up of Parker's flat in Meadowfoot Road, lifting carpets, replacing floorboards and bleaching it from top to bottom.

Coats and Wade also threatened potential witnesses, many of whom told the court that they were terrified and disgusted by what they learned.

Coats came up with a story to suit the circumstances of Ms Spence's mysterious disappearance, saying he helped his "close friend" when she needed to get out of Glasgow because she was being threatened and extorted by other business associates.

He said she organised the safe house independently with Smith and simply disappeared one day, along with Coats's laptop and Parker and Smith's drugs stash.

But the jury saw through his lie.

Forensic experts could only find one spot of blood at the Meadowfoot Road flat which matched Ms Spence's DNA profile. It was discovered on the bathroom floor, obviously missed as the men mopped up the rest of the mess.

Apart from this one physical clue, the Crown's case rested on circumstantial evidence.

Solicitor general Lesley Thomson urged the jury to look at all of the evidence which, she said, fits together like strands of a cable.

Police closed in on the Ayrshire area when the car used by Ms Spence was picked up by automatic number plate technology on the M77 near Floak. Both Coats's and Wade's phones were cell-sited in the area at the time.

Gossip spread around West Kilbride and Kilbirnie when Wade, Parker and Smith started hinting at what they had done. In one such instance, Wade confessed to his friend Pamela Pearson that he helped dispose of a body.

Jurors also heard that Coats used Ms Spence's thumb to threaten John Glen who he said owed him thousands of pounds.

The four men were snared by detectives on October 31 2011.

Parker and Smith were later cleared of murder when they admitted holding Ms Spence against her will at the instruction of Coats and Wade.

Coats and Wade always maintained their innocence but are now convicted of the woman's abduction, torture and murder.

Profile of Lynda Spence

Lynda Spence was portrayed in court as a con artist who spent other people's money like it was her own.

For a time, she lived a lavish lifestyle, eating at expensive restaurants and throwing back glasses of expensive champagne at bars, strip clubs and casinos.

The 27-year-old was generous with her cash, often paying for friends on nights out. She was confident and charming, making her likeable and, in turn, a lot of people trusted her with thousands of pounds of their money.

But Ms Spence was a "deal junkie". When she saw an opportunity to get hold of some fast cash, she took it.

At the time of her disappearance in April 2011, she was being investigated by Strathclyde Police over claims that she defrauded about 30 people in Glasgow. This involved a property development known as Lochburn Gate in Maryhill, for which Ms Spence is thought to have collected about £175,000 in deposits.

Ms Spence's Great Western Road business, Fraser Property Management, was set up using money her parents gave her from the sale of her grandmother's bungalow. But her life started to unravel as the company went under.

Former school friend and employee Amanda Robertson told how unhappy customers often came in demanding their money back and said staff there were rarely paid.

When the business folded, her parents' money went with it. They were made temporarily homeless when Ms Spence stopped paying their rent, as was the agreement when they helped her start up the property firm.

Ms Spence used a number of aliases and is said to have been involved in getting fake UK passports for people from Eastern European, and owed thousands of pounds to "various well-known criminals".

She was in the process of becoming a police informer for the Scottish Crime and Drug Enforcement Agency which authorised her to report back about the apparent criminal conduct of former partner Sokal Zefaj and three others.

Ms Spence got the seal of approval from the agency on April 14: the day she was abducted.

It was pointed out during the trial that despite learning much about Ms Spence's life, jurors still did not know "the half of" what she was into.

Ms Spence was close to her parents, James and Patricia, and her mother broke down a number of times as she told the court about her "loving, caring girl" with whom she spoke every day.

They last saw their daughter on April 13 2011 when Ms Spence visited her mother at her Castlebank Gardens home to give flowers for her birthday. When she left she told them: "I'll be back in half an hour.". She was never to return.

With her financial situation in tatters, Ms Spence was stressed and on edge before she vanished, telling people she would be in big trouble if a deal she was party to did not go through.

It became clear during the trial that Ms Spence dreamed up fictitious characters who were supposedly in charge of a large-scale land deal at Stansted Airport, said to be "worth millions".

She made up email accounts for someone called "Uncle Ben", allegedly the main investor, using the internet connection serving Rio Cafe in Glasgow which was known to her friends as "Lynda's Partick office".

"Uncle Ben" replied to emails from Colin Coats who invested £85,000 - all of his money - in the Stansted deal.

Ms Spence strung Coats along for the best part of a year, promising him a return of over £3 million when the deal went through. He asked for it in overseas bearer bonds as a way of evading UK tax.

She came up with the bonds but they were worthless, nothing more than a novelty forged on fake Danish government-headed paper.

Ms Spence met Mr Zefaj when she was 17 and working for the Co-operative Bank. It is unclear if they were ever married but Ms Spence used his last name as a way of bolstering herself in business.

Her friend Ms Robertson did marry him when she was 19 as a favour to Ms Spence, to keep Mr Zefaj in the UK.

Meanwhile, Aliona Codreanu, a "Gucci model" who Ms Spence claimed was her girlfriend, was said to be besotted with Mr Zefaj.

It was Ms Spence's financial dealings with Coats that eventually led to her brutal and untimely death. He and his friend Philip Wade employed Paul Smith and David Parker to hold her captive for almost two weeks as they inflicted extreme daily violence on her to try to get information from her.

Murder convictions without a body

Murder trials usually pose two questions for any jury: was the death a crime and was the person in the dock responsible?

But in cases which have no body, jurors are further asked: is the alleged victim even dead?

Such cases are relatively rare and the guilty verdict in the Lynda Spence murder trial is among only a handful of recent murder convictions where no body was ever found.

Only a single blood mark found next to the bath in David Parker's flat, in West Kilbride, Ayrshire, matched Lynda Spence's DNA. Without it, the financial adviser would have vanished completely.

Her body, which has never been found, is believed to have been stowed in the boot of her hire car, a Vauxhall Astra, and driven almost 50 miles to remote Argyll where Colin Coats and Philip Wade hoped to throw her into the Firth of Clyde.

Wade's friend, Lee Winyard, was suspicious at their overzealous requests to get out on his boat on April 29 2011 and he refused them.

Coats later confessed to a fellow inmate in Addiewell prison, West Lothian, that they put her body in a furnace.

Apart from the spot of blood next to the bath, which seems to have been simply overlooked by Coats as he scrubbed the bathroom, forensic scientists found no other evidence of Ms Spence being in the Meadowfoot Road property.

The leather chair to which she was taped for 13 days was burned and the floorboards that would have been beneath her were replaced.

Prosecutor Lesley Thomson QC, solicitor general for Scotland, said that although no body was found, the jury could conclude that Ms Spence is dead. She pointed to Ms Spence's lack of contact with her parents, with whom she was always in touch.

An extensive proof-of-life inquiry by Strathclyde Police found no clue about her whereabouts.

"This is not a woman choosing not to make contact. This is a young woman who cannot make contact, who cannot do anything because her life has been taken from her," Ms Thomson said.

Last year Nat Fraser was convicted of murdering his estranged wife Arlene, whose remains have not been found. Friends and family said the devoted mother would never have abandoned her two young children.

When she disappeared on April 28 1998, Ms Fraser was going about her normal business. The 33-year-old mother-of-two's bank cards, clothes and passport were found in the property, along with medication that she took daily for Crohn's disease.

Alex Prentice QC, prosecuting, told the jury the case against Fraser was circumstantial but that, from the evidence, it was "quite an easy task" to conclude Mrs Fraser is dead.

In April last year David Gilroy was jailed for 18 years for murdering his former lover and work colleague, Suzanne Pilley. The 38-year-old book-keeper disappeared on May 4 2010 while making her usual journey to work in Edinburgh city centre.

The prosecution case against Gilroy, 49, was also circumstantial but each part of it helped build a picture of increasingly suspicious behaviour and pointed to his guilt.

Married Gilroy killed Ms Pilley in the basement of the offices they shared and later took her body to a secret grave, believed to be in a remote area of Argyll. No trace of her has ever been found.

In 2010 paedophiles Charles O'Neill and William Lauchlan were found guilty of murdering a woman in Largs, Ayrshire, who planned to report them for abusing a boy. Her body has not been found.

Michael Topham was jailed for life in 1980 for murdering a man five years earlier. The body is thought to have been buried in a forest near the Queen's Balmoral Estate but efforts to find it were unsuccessful.

A timeline of torture

2011

April 13 - Lynda Spence visits parents in Castlebank Gardens, Glasgow, to give mother flowers for birthday - the last time they see her.

April 14 - Ms Spence abducted from Broomhill Path, Glasgow by Colin Coats and Philip Wade and taken to a flat in Meadowfoot Road, West Kilbride, Ayrshire, the home of David Parker.

She is taped to a chair and subjected to violence for up to two weeks - Parker and Paul Smith said they were offered money to "babysit" Ms Spence when Coats and Wade were not there.

April 20 - Silver Vauxhall Astra car hired for Ms Spence from Glasgow on April 1 picked up by automatic number plate recognition camera on M77 near Floak, Ayrshire.

April 20 - Ms Spence phones parents and says she will contact them again later - the last time they hear from her.

April 27 - Coats and Wade tell Parker and Smith they can leave flat. Ms Spence alive at this point.

April 29 - Coats and Wade visit Wade's friend Lee Winyard in Tighnabruaich, Argyll, and ask to use his boat to "get rid of something". He refuses.

May 13 - Ms Spence formally reported missing after fraud investigators call at parents' home.

June 2 - Mobile phone used by Ms Spence found in bin outside cafe in Kilbirnie, Ayrshire.

October 27 - Crown witness Pamela Pearson gives statement to police, saying Wade told her that he helped dispose of woman's body.

October 28 - Blood mark discovered on bathroom floor of flat in Meadowfoot Road found to have same DNA profile of Ms Spence.

October 31 - Police take Coats, Wade, Smith and Parker into custody.

2013

January 16 - Trial begins. Court hears Ms Spence was being recruited as police informer for Scottish Crime and Drug Enforcement Agency.

January 28 - Ms Spence's mother Patricia Spence gives evidence, weeping as she describes her "loving, caring girl".

March 6 - Parker and Smith cleared of murder when they plead guilty to holding Ms Spence against her will and assaulting her. They also admit attempting to defeat the ends of justice and agree to give evidence against Coats and Wade.

April 8 - Jury finds Coats and Wade guilty of murder.