Background to Blue Lagoon case
If the remains of Michael Gilbert hadn't moved through the murky waters of The Blue Lagoon, it's likely his killers would have got away with the murder.
Detectives say by the time of his death in January 2009, the 26 year old had little contact with his real family.
He was being held captive by the Watt family as their "slave and dogsbody."
Whenever he did manage to escape from their house he would get as far away from Luton as he could.
On the rare occasions he did visit his family, it was never for long and he would soon be off "to do his own thing."
It meant that after his body had been chopped up and dumped by the Watt brothers in the lake, there was no one to raise the alarm and report him missing.
Detetective Chief Inspector Jon Humphries who led 'Operation Pinlock' - the code name for the murder investigation launched by Bedfordshire and Hertfordshire Major crime Unit - said "Because Michael was in the habit of going missing and voluntarily absenting himself from is family, there is a very good chance that if the body hadn't turned up, his murder would have remained unsolved."
Michael's remains were found close to the banks of the lake - a former quarry which has been flooded - in May of last year by two men walking a dog.
But the body parts had been dumped in the lake on the opposite side four months earlier.
Over the months the remains had drifted several hundred yards to the other side.
Michael Gilbert had been a happy active youngster. He was of above average intelligence, he loved football, computer games and was good at maths.
But he had problems dealing with others, standing up for himself and he needed the close support of others.
Immature, trusting and naive, his family say he never grew up and even in his 20's was more like a young adolescent.
As a result he was vulnerable and an easy prey for the Watt family and in particular sadistic elder brother James Watt who took pleasure in humiliating and beating Michael.
Kept in the Watt home as the family's slave, it was James Watt who supervised his imprisonment, making sure he couldn't escape.
At night he would sleep under a bed occupied by one of the Watt brothers and his girlfriend.
Zoe Smith 23 said Michael would be shackled to the bed by a set of silver metal handcuffs as she slept with her boyfriend at the time, Colin Watt. He was one of the few members of the family not to be charged with any offence in connection with Michael's death
The bed was the lower bunk of a bunk bed and sleeping above them, she said, was another brother, Robert Watt.
Zoe said she was in a sexual relationship with Colin Watt - but when she stayed with him at the family home in Marlborough Road, Luton and Michael was sleeping underneath them, they never had sex.
She said during her three year relationship with Colin Watt she visited his home on at least 150 occasions and saw Michael assaulted nearly every time.
Michael was expected to do household chores for the Watt family and he was used to provide a cruel form of entertainment for the younger members and their friends.
They took pleasure in beating him for the fun of it.
Sometimes the assaults would be filmed on mobile phones.
He was frequently punched and slapped. On one occasions he pubic hair was set alight. On another mole grips were attached to his genitals and he was led around the house in agony. He was forced to stand in boiling hot water, he was struck by a baseball bat and was shot at with an air gun so that the pellets ended up embedded in his body.
James Watt's girlfriend Natasha Oldfield even wrote out details in her diary of a sick game show idea she had where participants could pay varying sums of money to assault Michael. It was £5 for a slap, £10 to punch him, £15 to kick him and £25 to head butt him. The notes even included the line "Gilbert ends up dead."
In addition to the violence being handed out to him, Michael Gilbert would be made to hand over his benefits to his captors who saw him as their "cash cow".
Whenever he did manage to escape the family were able to use the benefits system to track him down.
Knowing he would need to sign on and armed with his national insurance number, someone would pretend to be Michael to check where he was supposed to do that.
Family members would then turn up at the benefits office on the day to grab Michael and forcibly take him back to Luton.
Following the discovery of the remains last May in the Blue Lagoon near Arlesey in Beds, the police were soon able to identify them as Michael, even though his head and other parts were still missing.
Detectives then turned their attention to the Watt family who it was known Michael had been "living" with.
Outside the house in Marlborough Road it was noticed that a coping stone was missing from the top of a garden wall.
It was significant since a coping stone had been found inside the wrapping around the body parts when fished from the lake.
The stone had been used to weight them down and it was found to have come like a jig saw piece from the wall.
Police then turned up a vital piece of evidence when it was discovered a police camera had captured Nicola Roberts' Ford Escort car in the area of The Blue Lagoon just before 1.30pm on the afternoon of January 22 2009. Police now know Michael's remains were in the boot of the vehicle at the time.
Cell site analysis of mobile phones for that day showed James Watt and Robert Watt leaving Luton and heading to the vicinity of the lake.
More mobile phone records showed the brothers in the area of the lake later that same afternoon.
Just before 5pm a police camera again captured the Ford Escort heading towards The Blue Lagoon.
The remains had been discovered on the afternoon of May 10 and the following day police released the news to the media that the body parts of a unknown person had been found in the Blue Lagoon.
Police enquiries revealed that same morning James Watt had been behind the wheel of his black Renault Megan when he it was picked up on ANPR as he drove family members to the lake where they watched police officers.
Back at the Watt home in Marlborough Road police found remnants of a carpet that had been left outside.
A closer examination revealed it had been heavily bloodstained and attempts had been made to clean it.
It was noticed to that outside in the garden a second coping stone was missing from the wall.
That stone was recovered from the lake by a police diving team in February of this year inside a holdall that contained Michael Gilbert's head and other body parts.
Richard Watt had pointed out to detectives where his brother James had thrown the bag into the lake and the divers quickly located it.
Blue Lagoon 3
Recently Played Tracks
Now playing: The best feel good music