A reclusive millionaire was "completely in thrall" to a live-in tenant who starved him to death to steal his fortune, a court has heard.
Anthony Sootheran's body was found at his home, High Havens Farm, near South Newington, Oxfordshire, in March 2014.
The 59-year-old was "controlled" by Lynda Rickard, 62, who allowed his room to become a "foul, unhygienic cell", a prosecutor told Reading Crown Court.
She and her husband Wayne Rickard, 66, both from Banbury, deny murder.
Mrs Rickard admits forging wills in the names of both Mr Sootheran and his mother, Joy, as well as spending tens of thousands of pounds of their money, the jury has been told.
Oliver Saxby QC, prosecuting, said the millionaire apparently ate little food in the three weeks before his death.
He was "virtually immobile", allowing a large pressure sore to develop on his back, the prosecutor said.
In the view of a health expert, Mr Sootheran would have survived if he had been medically treated a week before his death, the jury heard.
He said a visitor in October 2013, Richard Stubbs, was "horrified" by Mr Sootheran's condition and the state of his room.
"The bed linen was stained and looked like it had not been changed in months. A window pane was broken. In the corner, there was a pile of Anthony's hair," Mr Saxby said.
"There was no television in the room. There were no books, or magazines. In short, it was a foul, unhygienic, cell."
The prosecutor said family members, Ian and Deborah Charles, met the millionaire in 2013 to discuss their suspicions about his mother's will.
He said: "[Mrs Rickard] kept prompting Anthony with his answers - he seemed to be looking to her for his cue and, in Mrs Charles' eyes, was completely in her thrall."
Other visitors were resisted or blocked by Mrs Rickard, who refused to give Mr Sootheran's daughter the code to the farm gates, the prosecutor said.
The victim died from a lung infection caused by malnutrition either on 18 March 2014 when his body was found or up to three days before, Mr Saxby added.
His forged will left the farm and a third of his £3.5m estate to Mrs Rickard, the jury has been told.
The Rickards were denied probate, lost a court challenge over the will and were evicted from the farm in 2017, the court heard.
As alternatives to the murder charge, Mrs Rickard denies gross negligence manslaughter, while her husband denies causing or allowing the death of a vulnerable adult.
They both deny fraudulently using Ms Sootheran's money to buy a Mitsubishi Shogun car.
Three of Mrs Rickard's friends, Shanda Robinson, 51, and Michael Dunkley, 49, from Banbury, and Denise Neal, 41, from Lower Tysoe, Warwickshire, deny fraudulently signing wills. However, another friend, June Alsford, 78, from Aynho, Northamptonshire, has admitted the charge.
Mr Rickard denies perverting the course of justice by attempting to pass off a will as genuine while Ms Robinson denies conspiring to do the same.
The trial continues.