Michael Gilbert's headless body was found at a gravel pit pool
A pathologist could not be certain how a man who had been kept a slave by a family had died, a court heard.
But Dr Nat Carey did find a stab wound that cut an artery and internal injuries on the decomposed corpse of 26-year-old Michael Gilbert.
Dr Carey told Luton Crown Court he discovered saw-like cuts on body parts recovered from a Bedfordshire lake.
The injuries could have killed Mr Gilbert, 26. Seven people are accused over the death.
It is alleged Mr Gilbert died last January at a house in Luton where he had been kept prisoner and treated as a slave.
The court has heard those responsible for his death covered their tracks by dismembering his body and dumping the parts in a lake known as The Blue Lagoon, near Arlesey.
The decomposing parts were found in May 2009 when they came to the surface and the head was discovered earlier this year in the lake.
Brothers James, 27, and Robert Watt, 20, deny murder. Richard Watt, 25, admits familial homicide.
Natasha Oldfield, 29, and Nichola Roberts, 21, also deny murder.
Robert Watt, Miss Oldfield and Miss Roberts also deny familial homicide.
Robert Watt and Miss Oldfield also plead not guilty to perverting the course of justice.
The brothers' parents Antonio Watt, 70, and Jennifer Smith-Dennis, 58, deny familial homicide and perverting the course of justice.
Rapid internal bleeding
Mr Gilbert is alleged to have died from injuries he received at a house where the family were living in Marlborough Road, Luton.
It is alleged by the prosecution that he was held prisoner by the Watt family for years and treated like a slave.
Dr Cary said the body parts were in an advanced state of decomposition which made assessment of internal organs and bruise marks more difficult.
He found evidence that soft tissue had been cut with a sharp object like a knife but a saw, meat cleaver or hatchet had been used to cut through bone and sever the head.
Three stab wounds were found on the torso and internal injuries to the stomach and intestine had been caused by people jumping on the man.
The aorta artery had been pierced and this would have been quite capable of causing death due to rapid internal bleeding .
However, he could not say if the stab wounds had been inflicted before or after death.
He said the stab wound and the internal damage could have been capable of causing the death but added "that's not to say that was the cause of death".
The trial continues.