A recently completed investigation of the killing of Daniel Pearl in Pakistan nine years ago makes public new evidence that a senior al-Qaeda operative executed the Wall Street Journal reporter.

Khalid Sheik Mohammed -- the self-described mastermind of the Sept. 11, 2001, attacks, who is being held at the U.S. detention center at Guantanamo Bay, Cuba -- said at a military hearing in 2007 that he killed Pearl. But there have been lingering doubts about his involvement, and the United States has not charged him with the crime.

According to the new report, which was prepared by faculty members and students at Georgetown University, U.S. officials have concluded that vascular technology, or vein matching, shows that the hand of the unseen man who killed Pearl on video is that of Mohammed. The report also says Mohammed told the FBI that a senior al-Qaeda operative advised him to take control of Pearl from his original kidnappers.

The 31,000-word report, published in conjunction with the Center for Public Integrity at www.publicintegrity.org, is among the most complete and graphic accounts of Pearl's death. The 3 1/2-year investigation, called the Pearl Project, was led by Asra Q. Nomani, a former colleague of Pearl's at the Journal, and Barbara Feinman Todd, director of the journalism program at Georgetown.

Pearl, 38, was kidnapped on Jan. 23, 2002, while investigating alleged connections between a radical Pakistani cleric and Richard Reid, who had attempted to detonate a bomb hidden in his shoe on a transatlantic flight in December 2001.

Pearl was duped into thinking that he was heading to an interview with the cleric when he was seized by a group of militants organized by Omar Sheik, a British-educated Pakistani, who is in prison for Pearl's kidnapping and murder, as are three accomplices. At the time he was orchestrating Pearl's abduction, the United States was pressing Pakistan for Sheik's extradition.

The report concludes that while Sheik set the kidnapping in motion, the group was uncertain about its ultimate goals and, at one point, appeared to consider releasing Pearl. According to the report, Mohammed told FBI interrogators at Guantanamo Bay that he received a call from Saif al-Adel, an Egyptian and a senior figure in al-Qaeda.

Adel "says, 'Listen, he's been kidnapped. These people don't know what to do with him. They want to know if we want him,' " Mohammed told the FBI, according to the report, which is based on hundreds of interviews as well as court records, FBI reports, and Pearl's e-mails and personal notes. Adel "thought this was an opportunity. We can take advantage of it. He said he wanted to make sure it's an Al Qaeda thing."

The report said it is still unclear how Adel, who remains at large, was able to direct Mohammed to the kidnappers.

The report said Mohammed and two others arrived at the compound on the outskirts of Karachi, where Pearl was being held. According to the report, some U.S. and Pakistani officials think the accomplices were Mohammed's nephews, including Ali Abdul Aziz Ali, who is also being held at Guantanamo Bay.

Mohammed slashed Pearl's throat, killing him, but one of his accomplices failed to operate the video camera, which they had brought to capture the murder for propaganda purposes. Mohammed restaged the killing, this time decapitating Pearl, according to the report. He then dismembered Pearl's body, and it was buried on the compound. Guards washed the bloody floor and then prayed, foreheads to the ground, on the same surface where their prisoner had just been killed, the report said.

The report said that 27 men, including guards and drivers, played a part in the kidnapping and murder, and that 14 remain free in Pakistan. Mohammed has not been charged with Pearl's murder, in part because he first confessed while in CIA custody, where he was waterboarded 183 times. Prosecutors fear that his treatment at the hands of the agency could compromise any case, the report said.

Mohammed told the FBI that he wanted to exploit the murder for propaganda. But the report also quoted a former chief military prosecutor at Guantanamo Bay as saying that "one of the high value detainees told interrogators that Osama bin Laden was angry that [Mohammed] had slaughtered Pearl so publicly and brutally, arguing that the murder brought unnecessary attention on the network."