The son of the Earl of Shaftesbury has told a French court his "manipulative, scheming and evil" stepmother betrayed his father and had him murdered.
The 12th Earl of Shaftesbury said his stepmother was an "evil person"
"You caused the death of an innocent man and you caused my family a lifetime of hurt," Nicholas Ashley-Cooper said.
Jamila M'Barek and her brother Mohammed both deny the murder charge saying the earl, who had homes in Hove and London, was killed during a drunken row.
During his statement Lord Shaftesbury called his father a "gentle soul".
He told the court in Nice: "We have heard the words of Mohammed and Jamila and we have seen the evidence brought before us.
"It confirms the type of people we thought they were - cold, deceitful, and without compassion for a man they murdered and betrayed."
The 12th Earl of Shaftesbury also directly addressed Ms M'Barek, saying: "Jamila, I do not believe that you ever loved my father and I believe that you are manipulative and scheming, and ultimately an evil person."
He said the spirit of his brother Anthony, who died of a heart attack in 2005 aged 27, was with him as he spoke.
Lord Shaftesbury said he only met Ms M'Barek once in London, when his father announced their marriage, but she had spoken to him in an attacking way.
He added: "At this point I knew immediately this person was extremely manipulative and willing to go a long way to get what she wanted."
The prosecution say Ms M'Barek paid her brother to kill the earl, because he was in the process of divorcing her and she feared being left out of his will.
Ms M'Barek claims the earl was killed accidentally during an argument that blew up between her husband and brother, who were both drunk.
She also denied marrying him for money saying she was already prosperous.
Mr M'Barek was thrown out of court on Thursday for yelling at the earl's family.
The playboy aristocrat went missing from the French Riviera on 5 November 2004.
His body was found in the foothills of the French Alps five months later.
The jury has retired to consider its verdict.