Who Killed Daniel Pearl?

CNN/AP Wall Street Journal reporter Daniel Pearl with a gun to his head

A Pakistani court has sentenced to death one man, Ahmad Omar Saeed Sheikh, 28, and imprisoned three others for their roles in the abduction and murder of Wall Street Journal reporter Daniel Pearl a year ago in Karachi. But the mystery of who wielded the knife that beheaded Pearl is still unsolved. Now Pakistani police sources tell TIME that at least one witness says Pearl's throat was slit by a top al-Qaeda terrorist, Khalid Shaikh Mohammed. A Kuwaiti of Pakistani descent, Mohammed is believed by U.S. authorities to have been a key organizer of the Sept. 11 hijackings.

A suspect in the abduction, Afghan war veteran Fazal Karim, has identified Mohammed as the man who drew the knife across Pearl's throat, two men who participated in Karim's interrogation tell TIME. Karim was detained in a Pakistani crackdown on militant groups last May, and he admitted he assisted in Pearl's abduction. During his interrogation, Karim confessed that he had helped three unknown Arabs carry out Pearl's murder. With Karim's aid, one Arab pinned the journalist to the floor while another wielded the weapon. The third videotaped the grisly act. The two officials who grilled Karim tell TIME that when the militant was asked to identify the Arabs from a stack of photographs, he stabbed his finger at Mohammed's picture and told police it was Mohammed who handled the knife.

Despite this fresh evidence, Pakistani police working on the Pearl case notice a distinct cooling in their superiors' interest. Saeed and his co-defendants are appealing the verdict, and Karim's testimony may weaken the government's case that Saeed was both ringleader of the plot and Pearl's executioner. Until the Pakistani Supreme Court rules on Saeed's appeal, say police, it is doubtful that kidnapping charges will be brought against Karim, who is in custody. Meanwhile, the search is on for Mohammed, who investigators think is still hiding in Pakistan.