A jury in London's Old Bailey criminal court found Prince Saud Abdulaziz bin Nasser al Saud guilty of murdering Bandar Abdullah Abdulaziz at the Landmark Hotel in London on Feb. 15.
The 34-year-old prince, whose grandfather is a brother of the current Saudi king, faces a possible life prison term in prison when he is sentenced on Wednesday.
The jury deliberated 95 minutes before returning its verdict.
Prosecutor Jonathan Laidlaw said the prince had abused his aide in the past, showing jurors video shot in the Landmark's elevator which appears to show the shaven-headed prince, dressed in white, throwing his 32-year-old servant around and battering him. Photographs of Abdulaziz stored on a mobile phone "plainly proved" that there was a "sexual element" to the abuse, Laidlaw said.
"The prince was fuelled by champagne and 'sex on the beach' cocktails when he bit the 32-year-old hard on both cheeks during the attack in February," the U.K.'s Telegraph newspaper reported.
Al Saud believed he would be protected from prosecution in the U.K. because of diplomatic immunity, the Telegraph reported.
He faces a likely death sentence if he returns to Saudi Arabia, not because of the murder but because he is gay and homosexuality is a capital crime there.
"The murder of Mr Abdulaziz was the final act in a 'deeply abusive' master-servant relationship in which the prince carried out frequent attacks on his aide 'for his own personal gratification,'" the Telegraph said.
Al Saud originally told police that he and Abdulaziz had been drinking into the early hours of the morning, and that when he awoke at 3 p.m. he could not rouse Abdulaziz.
Jurors rejected a claim by his defense lawyer John Kelsey-Fry that the prince was guilty only of manslaughter.
The prince was convicted of both murder and a second count of grievous bodily harm with intent relating to the attack in the elevator.
"Beneath the surface this was a deeply abusive relationship which the defendant exploited, as the assaults in the lift so graphically demonstrate, for sadistic reasons, for his own personal gratification," Laidlaw told the jury.
"The abuse extended beyond physical abuse. There was plainly an emotional element and psychological element to it."
The prosecutor said Abdulaziz surrendered meekly to the fatal assault.
"He was killed without apparently ever having fought back because the defendant was completely unharmed, without any mark at all, when he was examined at the police station. Bandar appears to have let the defendant kill him," Laidlaw said.