A former close aide to Osama bin Laden who became a crucial witness for the United States government after he defected from Al Qaeda more than 15 years ago has asked to be sentenced without further delay, an act that could breach his cooperation agreement with prosecutors.
The former aide, Jamal Ahmed al-Fadl, a Sudanese man who remains in hiding, fears that his six children will be sent back to Sudan, where bin Laden was once based, his lawyer, Ira D. London, recently told a judge in Federal District Court in Manhattan.
“What he wants the court to be aware of is that if his children are taken from the United States and returned to the Sudan,” Mr. London said, “they will certainly be killed by the people he has cooperated against.”
“It is his promise to his children that that will not happen,” Mr. London added.
Mr. Fadl pleaded guilty in 1997, was placed under witness protection and was to be sentenced after his cooperation in the investigation of the terrorist group ended.
Mr. London did not explain in court how an accelerated sentencing would enable his client to address the issue of his children, or what had triggered his client’s concern.
But the request highlights the risks and complications — for prosecutors and cooperators — in long-running investigations in which both sides depend so greatly on each other.
Mr. Fadl’s cooperation began after he entered a United States Embassy in Africa in 1996, and offered his help. He later acknowledged that he had stolen money from bin Laden, and he eventually pleaded guilty to conspiracy.
In early 2001, Mr. Fadl took the witness stand in the trial stemming from the deadly 1998 bombings of two American Embassies in East Africa, offering riveting testimony about Al Qaeda’s origins, its leadership and its plots.
The government’s agreements with cooperators typically mandate that the government decides when a witness will be sentenced. This can give the government more leverage over a witness. But a delay can benefit witnesses, too, allowing them more time to provide assistance, which ultimately may help them win leniency at their sentencing.
In court last month, a prosecutor, Nicholas Lewin, told the judge, John G. Koeltl, that the government did not favor sentencing Mr. Fadl at least until after a trial of two more Qaeda defendants that is scheduled for next fall. There was a “substantial possibility” that Mr. Fadl would be asked to testify, Mr. Lewin said.
Mr. Fadl indicated through another lawyer that he wanted “immigration issues that are very important to him and to his family” resolved before that trial.
Neither prosecutors nor Mr. London would comment Tuesday. But in court, Mr. London, who had just been appointed in the case, said that after an initial conversation with his client, “he has been rather adamant that he wants to proceed to sentence.”
“The ramifications of that are grave for him, because that will undoubtedly breach his cooperation agreement,” Mr. London said.
Breaching a cooperation agreement can lead the government to withhold support for leniency at sentencing, although prosecutors would retain the discretion to make a final judgment.
Mr. London said that his client wanted him “to communicate to the court, and probably more so to the government, that his primary concern in all of this is the future of his children.”
Mr. Lewin, the prosecutor, responded that the government understood the concern, and was addressing the issue.
Mr. Lewin said that Mr. Fadl had been “an extraordinarily important witness,” who had put himself and his family at risk. Their safety “is of the greatest importance to the government,” he said.