By Chris Summers
BBC News website
Two men have been convicted of murdering businessman Amarjit Chohan, his wife, their two small children and his mother-in-law. A third man was convicted of murdering Mr Chohan alone and assisting an offender.
The police investigation was long and fraught with difficulties but ultimately successful.
From his watery grave Amarjit Chohan left detectives a vital clue which eventually helped convict his killers.
Amarjit Chohan secreted this letter in his sock, knowing it would incriminate Regan
A scrap of paper was found inside one of his socks.
It was a letter addressed to Kenneth Regan at his father's home in Forge Close, South Newton, near Salisbury, Wiltshire.
Police believe Mr Chohan was tied up and held captive at this house for several days prior to being killed.
Mr Chohan, suspecting he was going to be killed, apparently decided to use that letter to give the police a clue about his killers.
Ironically the note was overlooked when the body was first examined. It was only months later, when forensic scientists were examining the sock, that they discovered the piece of paper.
Detective Chief Inspector David Little said that although the letter was soaked with seawater, the ink remained legible because it had been folded over many times - always with the ink on the inside.
Mobile phone evidence
Police eventually pieced together the sequence of events which had led to the massacre of the Chohan family.
One of the biggest things in their favour was cell site analysis evidence from the defendants' mobile phones and those of their victims.
This showed Mr Chohan travelling towards Stonehenge on 13 February 2003, the day he was abducted, and also placed Regan, Bill Horncy and Peter Rees in key areas at key moments during the saga.
Amarjit Chohan, pictured with his baby son, left behind a vital clue
Rees never ventured far from the house in Forge Close, where he was guarding the prone Mr Chohan.
Regan and Horncy travelled further afield. Their phones placed them in the vicinity of the Chohan family home in Sutton Road, Hounslow, on the day they went missing.
They were also traced to the area around Belinda Brewin's farm at the time when the bodies were being buried.
After the Chohans vanished Regan appeared at Ciba Freight's office, armed with a bogus power of attorney signed by Mr Chohan who, he claimed, had sold up and fled the country.
Because of Mr Chohan's reputation - he had served time in prison for tax evasion - most of the Ciba staff believed Regan's story.
Police believe Mr Chohan was tortured and killed in Regan's home
Their suspicions grew, however, and one worker, Barry Joyson, took Regan's laptop computer home.
Police later found several incriminating documents on it, including a copy of a fake letter purporting to have been sent by Mr Chohan from Calais.
They later recovered other fake documents, including a letter from Mr Chohan to his Ciba colleague, Mike Parr, saying he was heading to Bradford to avoid having to pay £3m.
In April, as police closed in, Bill Horncy claimed to have received a threatening text message from someone who claimed to have seen them at a rendezvous in Newport, South Wales.
It supposedly said: "We know you tried to get us arrested the other day. We saw the police sitting in a car by the taxi. You are a bastard and an informer. You are finished."
When detectives asked to see the message Horncy claimed his niece had accidentally deleted it.
But although they suspected foul play police were only able to prove it when they found out about Belinda Brewin's farm.
She mentioned it on 29 April 2003 while being interviewed about Regan. The following day police excavated a trench in the grounds of the farm, uncovering DNA belonging to Mr Chohan, scraps of clothing and jewellery and other incriminating items.
Police spent several days searching the field in Devon
Regan and Horncy knew the game was up.
Escaped in the night
They drove from Tiverton to Bournemouth - where Horncy lived - collected some belongings and travelled to Ciba Freight's offices near Heathrow.
Horncy searched in vain for Regan's laptop computer before the pair boarded an overnight Dover ferry to Calais.
Rees arranged accommodation for them in Spain but he decided to hide out in Gloucestershire, where he was arrested two weeks later.
Regan and Horncy stayed on the run throughout the summer. Regan was arrested by police in Ghent, Belgium, in August and Horncy gave himself up to police at Dover shortly afterwards.
Charanjit Kaur was on holiday with her daughter and son-in-law
But despite overwhelming evidence the trio continued to protest their innocence.
All three pleaded not guilty at the Old Bailey trial, although Rees sought to distance himself from the other two and claimed he had been duped by Regan, who he said he had always disliked and distrusted.
Regan continued to maintain his story - that he was forced to dispose of the bodies by a gang of Asians who had killed the Chohans in a row over smuggling a narcotic shrub called khat and was threatened with dire consequences if he did not do so.
But the jury saw through the lies and returned a guilty verdict.