Suspect and A Setback In Al-Qaeda Anthrax Case

Investigation Breaks Down

Rauf's detention kicked off a joint U.S.-Pakistani investigation that at first was remarkably successful.

"There was great cooperation at the start," said one U.S. intelligence official who closely followed the case.

The FBI's New York office took the lead U.S. role, and its agents worked closely with the CIA and bureau officials in Pakistan in carrying out interrogations. Though not formally charged with any crimes, Rauf consented to questioning and provided useful leads, U.S. and Pakistani officials said. But problems began when the U.S. side sought to expand the investigation with the goal of pursuing criminal charges, including possible indictment and prosecution in the United States, officials from both countries confirmed.

In earlier cases, the Pakistani government incurred the wrath of Islamic leaders when it sought to prosecute professionals for alleged ties to al-Qaeda.

In 2003, the Pakistanis shut off U.S. access to Rauf. According to Pakistani officials familiar with the case, there simply was not enough evidence showing that he succeeded in providing al-Qaeda with something useful.

Since then, Rauf has been allowed to resume his normal life. Whether he has returned to his former workplace is unclear; officials at the research council declined to respond to requests for information about the scientist. Attempts to contact Rauf in Lahore were unsuccessful.

"He was detained for questioning, and later the courts determined there was not sufficient evidence to continue detaining him," said Tariq Azim Khan, Pakistan's information minister. "If there was evidence that proved his role beyond a shadow of a doubt, we would have acted on it. But that kind of evidence was not available."

Special correspondent Kamran Khan in Karachi, Pakistan, contributed to this report.