Dr Richard Shepherd, a forensic pathologist, said that Khalid Dad's head was severed by a single blow. 'A woman or man would be capable of delivering this blow with a suitable weapon,' he said.
Majid Syed, 60, and his sons Moddessir Jafri, 24, and Kauser Jafri, 21, deny murdering Mr Dad, 21, of Slough, Berkshire in May last year.
Dr Shepherd said Mr Dad had been forcibly restrained, his wrists and ankles had been tied with rope and he had been gagged. Before his death Mr Dad had been beaten with a blunt object.
'He was attacked from behind, he must have been kneeling, head down, presenting a large surface area. The tip of the blade exited through his arm pit,' he said.
Dr Shepherd described the weapon as 'at least 2ft with a very long and sharp blade'. He estimated the time of death as between midnight and 6am.
Mr Dad's head was discovered in a black plastic bag in the gutter of Waterbeach Road on 21 May 1991 by a motorist who thought someone was playing a joke.
In a written statement to the court Akhter Suleman said: 'I didn't believe that it could possibly be a human head and thought it must be a plastic one that was being used as a joke.'
Mr Dad's body was found half a mile away wrapped in a bedspread in a school driveway.
Police found Mr Dad's blood- stained clothing and some rope in Mr Syed's loft. There were also splashes of blood on the dining room walls and floors.
The prosecution alleges Mr Syed and his sons used foam from a sofa to soak up Mr Dad's blood. Police found blood-stained foam with the body, in Mr Syed's loft and on a bonfire in the garden.
David Brace, a scenes of crime officer, said that he had found blood and fibres in Mr Syed's car.
The trial continues today.Reuse content