01/04/2015 12:02 EST | Updated 03/05/2015 05:59 EST

Accused al-Qaeda terrorist Abu Anas al-Libi dies in U.S. custody

A suspected al-Qaeda terrorist charged in the 1998 attacks on embassies in east Africa that killed more than 200 people has died in federal custody days before his trial was to start, a U.S. official said Saturday.

Manhattan U.S. Attorney Preet Bharara said in a court filing that Abu Anas al-Libi, who's also known as Nazih Abdul-Hamed al-Ruqai, died Friday in a local hospital from sudden complications "arising out of his long-standing medical problems."

Al-Libi, 50, had pleaded not guilty to charges he conspired in the simultaneous attacks on embassies in Tanzania and Kenya that killed 224 people, including a dozen Americans. His family and former associates denied he was ever a member of al-Qaeda.

His federal trial was to begin Jan. 12 in Manhattan.

Al-Libi was captured by units from the U.S. Army's elite Delta Force in October, 2013, and flown to a navy ship in the Mediterranean before being brought to the U.S.

Al-Libi, once wanted by the FBI with a $5-million bounty on his head, was chronically ill with hepatitis C when the soldiers seized him. His wife, who asked to be identified as Um Abdullah, told The Associated Press that his experience only worsened his ailments.

"I accuse the American government of kidnapping, mistreating, and killing an innocent man. He did nothing," Um Abdullah said.

Al-Libi, which means "of Libya" in Arabic, was his nom de guerre. U.S. prosecutors in 2000 described al-Libi as sitting on a council that approved terrorist operations for al-Qaeda, which would become infamous worldwide a year later after the Sept. 11 terror attacks.

Before that, al-Qaeda's Aug. 7, 1998, truck bombings at the U.S. embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania, were its deadliest assault. The bombs tore through the embassies and nearby buildings, killing 213 people and wounding about 4,500 in Kenya alone. The Tanzania attack, conducted minutes later, killed 11 people and wounded 85.

Surveillance on embassy

Al-Libi, believed to be a computer specialist for al-Qaeda, conducted visual and photographic surveillance of the U.S. Embassy in Nairobi in late 1993, the federal court indictment against him and others alleges. In 1994, he and other al-Qaeda members researched alternate potential sites in Nairobi including the local office of the U.S. Agency for International Development, as well as "British, French and Israeli targets," according to the indictment.

His path to Kenya and al-Qaeda remains unclear. Al-Libi is believed to have spent time in Sudan, where Osama bin Laden was based in the early 1990s. After bin Laden was forced to leave Sudan, al-Libi turned up in Britain in 1995 where he was granted political asylum under unclear circumstances and lived in Manchester.

He was arrested by Scotland Yard in 1999, but released because of lack of evidence and later fled Britain. After his indictment in December 2000 over the embassy bombings, U.S. officials said they believed he was hiding in Afghanistan.

Al-Libi later said in court filings that he returned to Libya as dissent against dictator Moammar Gadhafi grew into an open revolt that led to the leader's downfall and killing in 2011. He said he "joined with forces of NATO and the United States" to replace Gadhafi, hoping to establish a "stable Islamic secular state."

Nabbed in Tripoli

In October 2013, the U.S. Army's Delta Force swooped into Tripoli and seized al-Libi after dawn prayers, his brother Nabih al-Ruqai said. Al-Libi said the soldiers took him to the USS San Antonio, where CIA agents interrogating him warned the questioning would be the "easiest step" of three.

"I took this to mean that the physical and psychological torture would only increase if I failed to cooperate with my questioners," he said in a court affidavit. "These threats continued the entire time I was on board the ship."

Al-Libi's lawyer, Bernard Kleinman, argued his client didn't plan the bombing.

"This case involves issues much more tinged with emotion and trauma than other cases," Kleinman said in 2013. "The fact that Mr. al-Libi will be tried in New York, barely a half mile from the World Trade Center site, and that Osama bin Laden and al-Qaeda will be referenced numerous times in connection with his co-defendants cannot be ignored."