Michael Gilbert's headless body was found at a gravel pit pool
A man has told a court how his family admitted murdering their "slave" before chopping up his body and dumping it in a Bedfordshire lake.
The decapitated body of 26-year-old Michael Gilbert was found in the Blue Lagoon in Arlesey last May.
Colin Watt told Luton Crown Court his brother Robert had said Mr Gilbert had been killed and his body cut up.
Robert and James Watt, of Chertsey Close, Luton, deny murdering Mr Gilbert on or about 21 January last year.
James Watt, 27, and Robert, 20, are also accused of familial homicide.
Luton Crown Court heard Mr Gilbert was made to sleep handcuffed to a bed to stop him escaping.
Head cut off
The prosecution said the victim had suffered years of violence before being killed, his body dismembered and head cut off.
Colin Watt told the jury he had moved out of the family home shortly before Mr Gilbert's death.
He said he had witnessed increasing violence towards Mr Gilbert by members of his family and said: "It made me feel ill. I thought I can't take no more of it, I am going."
He told the court that Robert Watt had asked him to go home because they had something to tell him.
"Robert said 'we killed Michael'," Colin Watt told the court. "I just walked out crying."
He said beatings would take place day and night and that by January 2009 there would be occasions when Michael could only crawl to move around.
He said: "He was turning a totally different colour."
Antonio Watt is among six people facing charges
The brothers' father Antonio Watt, 70, of Chertsey Close, is charged with familial homicide and perverting the course of justice.
Their mother, Jennifer Smith-Dennis, 58, is charged with familial homicide and two counts of perverting the course of justice.
Nichola Roberts, 21, of Burfold Close, Luton, the girlfriend of the accused men's brother, Richard Watt, is charged with murder, familial homicide and perverting the course of justice.
Natasha Oldfield, 29, of Chertsey Close, who is the girlfriend of James Watt, faces the same charges as Ms Roberts.
The court heard Mr Gilbert met James Watt when they were both 15 and living at a children's home.
Mr Gilbert was introduced to the Watt family and went to live with them.
He escaped on a number of occasions but each time he was found and made to return, jurors were told.
The case continues.