After 18 years of denial, the main accused, convicted and later acquitted, in the 2002 beheading of American journalist Daniel Pearl has told a court he played a "minor” role in the killing, the Pearl family lawyer said on Wednesday.

A letter handwritten by Ahmad Saeed Omar Sheikh in 2019, in which he admits limited involvement in the killing of the Wall Street Journal reporter, was submitted to the Supreme Court nearly two weeks ago. It wasn't until Wednesday that Sheikh's lawyers confirmed their client wrote it.

Nowhere in the three-page letter addressed to the Sindh High Court (SHC) did the British-born Sheikh elaborate or say exactly what his allegedly minor role in Pearl's slaying involved.

Daniel Pearl, 38, was doing research on religious extremism in Karachi when he was abducted in January 2002. A graphic video showing his decapitation was delivered to the US consulate a month later. Subsequently, Omar was arrested in 2002 and sentenced to death by a trial court.

In its April 2, 2020, order, the SHC had overturned the conviction of Omar Sheikh for killing the South Asia bureau chief of The Wall Street Journal. The SHC had also acquitted three other men namely Fahad Naseem, Sheikh Adil and Salman Saqib, who had been earlier sentenced to life imprisonment by an Anti-Terrorism Court (ATC) in Karachi.

Subsequently, the Sindh government as well as the parents of Pearl had filed separate appeals against the SHC's order in the Supreme Court.

On Wednesday, the Pearls' family attorney, Faisal Siddiqi, called Sheikh's confirmation that he wrote the letter a dramatic development and demanded that the conviction and the death sentence for Sheikh be reinstated.

"This is very, very important because for the last 18 years, the position of Omar Saeed Sheikh was that he did not know Danny Pearl, he never met Danny Pearl,” Siddiqi told The Associated Press. "He had taken a position of complete ignorance regarding this case, but now in a hand-written letter, he has admitted to at least a limited role.” He has not asked that he be acquitted. He accepts his guilt but asks that his sentence may be reduced, he added.

In the letter, Sheikh writes that his role in the matter was a relatively minor one, which does not warrant the death sentence. A copy of the letter was obtained by the AP.

Read: Omar Saeed Sheikh — from rowdy student to terror convict

Sheikh also admits to knowing who killed Pearl and alleges it was another militant, Atta-ur-Rahman, alias Naeem Bokhari, who has since been executed in connection with an attack on a paramilitary base in Karachi.

In the letter, dated July 25, 2019 and stamped with the seal of the SHC, Sheikh asks that he be given an opportunity to "clarify my actual role in this matter so that my sentence may be reduced accordingly to one which is consistent with the requirement of justice".

However, Sheikh's lawyer, Mehmood A. Sheikh, insisted that his client wrote the letter under duress and that he did not know or have any connection to Pearl.

The lawyer, who is not related to Sheikh, said his client described the conditions in his prison as worse than the life of an animal and wrote the letter in an attempt to get a hearing, not make an admission of guilt. He wanted to be able to be heard, the lawyer said.

The appeal is expected to wrap up this week, said Siddiqi, the Pearl family attorney. He said he expects a quick decision after Sheikh's admission of involvement, even in a minor capacity, in Pearl's death.

“This changes everything,” he said of the letter.

Sheikh was convicted of helping lure Pearl to a meeting in Karachi, during which he was kidnapped. Pearl was investigating the link between militants and Richard C Reid, dubbed the 'Shoe Bomber' after trying to blow up a flight from Paris to Miami with explosives hidden in his shoes.

Sheikh was sentenced to death and three other suspects were sentenced to life in prison for their roles in the plot. The acquittal last April stunned the US government, Pearl's family and journalism advocacy groups.

Last month, acting US Attorney General Jeffery Rosen warned that the US would not let Sheikh go free, saying if those efforts do not succeed, the United States stands ready to take custody of Omar Sheikh to stand trial in America.