A Wall Street Journal reporter, Pearl was kidnapped in Pakistan`s biggest city of Karachi in January 2002 while researching a story on Islamist militants, and was later beheaded.
The findings by investigators of the Pearl Project revealed al-Adel had discussed Pearl`s abduction with Khalid Sheikh Mohammad, also known as KSM, the accused mastermind behind the Sept. 11, 2001, attacks on the United States.
"KSM told the FBI that he was pulled into the kidnapping by a high-level leader in al Qaeda circles, an Egyptian named Saif al-Adel, who told him to make the kidnapping an al Qaeda operation," said the investigators in their report which was published in January.
Journalism academics and students set up the Pearl Project at Georgetown University in the United States to investigate Pearl`s kidnapping and murder.
The linkage of al-Adel to Pearl`s murder shows the long-standing ties between al Qaeda and Pakistan militancy, which flourishes not only in the lawless northwest along the Afghan border but in Karachi and other urban centers.
Pearl fell into al Qaeda`s hands after Pakistani militants, the subject of Pearl`s research, kidnapped him.
Al-Adel learned of Pearl and approached Mohammad to take him off the Pakistani militants` hands.
"He (al-Adel) thought this was an opportunity," Mohammad told FBI agents, according to the report`s authors.
"We can take advantage of it. He said he wanted to make sure it`s an al Qaeda thing."
Mohammad, who was arrested in Pakistan in 2003 and taken to the U.S. prison at Guantanamo Bay, later admitted he beheaded Pearl.
Mohammad told investigators he initially had no idea about the kidnapping and he also said al Qaeda leader Osama bin Laden was reportedly angry over Pearl`s brutal killing, the report said.
A former chief prosecutor for Guantanamo Bay military commissions told the researchers: "One of the high value detainees told interrogators that Osama bin Laden was angry that KSM had slaughtered Pearl so publicly and brutally, arguing that the murder brought unnecessary attention on the network."
A British-born Islamist militant, Ahmed Omar Saeed Sheikh, was sentenced to death by a Pakistani court in 2002 for his role in Pearl`s killing. He has appealed his conviction. Three other
co-accused who face life sentences, have also appealed.
Al-Adel, the latest militant named in connection with Pearl`s murder, was appointed al Qaeda`s temporary leader following the killing of bin Laden by U.S. special forces in a Pakistani town on May 2.
U.S. prosecutors say al-Adel is one of al Qaeda`s top military commanders and helped plan 1998 bomb attacks on the U.S. embassies in Kenya and Tanzania. They also say he set up al Qaeda training camps in Sudan and Afghanistan in the 1990s.