ISLAMABAD, Pakistan — A Pakistani court on Thursday overturned the murder conviction and death sentence of Ahmed Omar Sheikh, a British-born militant who had been convicted of masterminding the 2002 abduction and killing of the American journalist Daniel Pearl, lawyers said.

The court also overturned the convictions of three other men who had been serving life sentences in the case. All four men were expected to be freed soon, lawyers said.

Mr. Pearl, a reporter for The Wall Street Journal, was abducted in January 2002 in the city of Karachi, while working on an article about Pakistani militant groups with links to Al Qaeda. He was later beheaded.

A two-member bench of the Sindh High Court in Karachi, headed by Justice Mohammad Karim Khan Agha, found that there had been sufficient evidence to convict Mr. Sheikh of kidnapping, but not of murder, said Mr. Sheikh’s lawyer, Khawaja Naveed Ahmed. “The court ruled that the charge of abduction was proven,” he said.