Mohammed Riaz, 33, allegedly kidnapped Mahmood Ahmad, 41, and tortured him to death in an attempt to track down his estranged ex-wife Nahid Ahmad, the Daily Mail reported Friday.
Riaz took the help of five accomplices to kidnap, imprison and murder Mahmood with a mechanical butcher's saw, St Albans Crown Court in Hertfordshire, England, heard.
Mahmood's remains have never been found and the gang was only arrested after a security guard found Mahmood's severed left thumb in a car park.
A prosecutor told the jury that CCTV footage captured the thumb falling mysteriously from the sky and police believe it might have been dropped by a bird which had picked it up, the report said.
Stuart Trimmer told the court that Riaz's obsession to find his estranged ex-wife led him to organise Mahmood's kidnap.
He said: "This was a planned rehearsed kidnap for the purpose of the torture and perhaps punishment of Mahmood Ahmad."
"The entire remains of Mahmood have not been recovered. But it will be quite clear that he was taken alive from outside his house in the early hours of March 7 last year and was killed and his body dismembered by March 10."
"The body of Mahmood was disposed of so efficiently that only a segment of the hand has been found," the court was told.
"CCTV footage shows it falling from the sky. How it fell from the sky is unclear, whether a bird took it is unknown."Riaz denies murder, conspiracy to kidnap, conspiracy to imprison and conspiracy to pervert the course of justice.
According to the daily, Mahmood from Watford, Hertfordshire, disappeared after leaving work March 7.The court heard that his severed left thumb, still attached to the knuckles of his left hand, was discovered by a security guard on a street in Ilford, Essex.
Trimmer told the court that Mahmood's brother-in-law Riaz exercised a reign of terror over his wife Nahid and her family - leading to a divorce.The trial continues and is expected to last eight weeks.