Edith Bartley knew the day would come. For almost 15 years, she and her mother have traveled to Manhattan from the Washington, D.C., area to attend the trials of men charged in a conspiracy that included al-Qaida's bombings of two U.S. embassies in East Africa.

Her reason for making the trips was deeply personal: Her father and younger brother were among the 224 victims.

So it was with some trepidation that she read a recent e-mail from federal authorities telling her that one of the defendants, Adel Abdel-Meguid Abdel-Bary, 60, was about to be released after 21 years in prison.

Abdel-Bary, an operative in London who on behalf of al-Qaida publicized a claim of responsibility for the attacks, is the only one of the men convicted in the plot known to be ready to leave prison, outside of cooperating witnesses.

Some of the men charged in the conspiracy, including Osama bin Laden, were killed by the U.S. or its allies. Seven conspirators are serving life sentences.

But Abdel-Bary, now in the custody of U.S. immigration authorities, has finished his sentence and is expected to be deported to Britain, his last place of residence.

To Bartley, the prospect that Abdel-Bary will be free, even in another country, is unsettling.

"Just serving a sentence doesn't mean that a person has been rehabilitated, doesn't mean that their core thinking has changed," Bartley said. "This is a person who can still do harm in the world."

His immigration lawyer R. Andrew Painter said, "After all this time, all Mr. Bary wants is to enjoy a quiet life with his family."

He has a wife in London and several children. One son, Abdel-Majed Abdel-Bary, who was a child when Abdel-Bary was jailed, was arrested in April by Spanish authorities and accused of having joined ISIS fighters in Syria.

It has been years since a series of high-profile terrorism trials were held in Manhattan, growing out of the 1993 World Trade Center bombing, which killed six people; an aborted plot to blow up New York landmarks; and the 1998 attacks on the embassies in Kenya and Tanzania.

More than a dozen terrorists were convicted in those and related cases and sentenced to life in prison. But some others have completed their sentences.

"Not everyone who is convicted of a terrible crime spends life in prison," said Nicholas Lewin, a former assistant U.S. attorney who helped prosecute Abdel-Bary. "People are released upon finishing their sentence," Lewin added. "It's fundamental to our system of justice."

Prosecutors say Abdel-Bary handled communications with the media for al-Qaida before and after the bombings. In 2015, he was sentenced to 25 years but received credit for the years he was jailed in Britain while fighting extradition, and also for good behavior in prison in the United States.

Susan Hirsch, a George Mason University professor, lost her husband, Abdurahman Abdalla, in the Dar es Salaam, Tanzania, bombing and wrote a book about what she has called "a victim's quest for justice."

Hirsch acknowledged Abdel-Bary's 21 years constituted a substantial sentence but said, "It's on the lower end of just, as far as I'm concerned."

The daughter of a third victim said she understood it made sense to grant some prisoners credit for the time they served before pleading guilty. "But for somebody who's done something this egregious, where so many people were killed," she said, for them "to have the possibility of going out and creating more havoc is actually terrifying."

After the nearly simultaneous embassy attacks on Aug. 7, 1998, bin Laden and more than 20 other al-Qaida operatives were charged with participating in a global conspiracy to kill Americans, which included the bombings.

As recently as this Aug. 7, one of the masterminds, Abu Muhammad al-Masri, was killed in Iran by two Israeli operatives at the behest of the U.S. Other operatives were sent to Manhattan for trials held in early 2001 and continued over the next decade and a half.

During those trials, Bartley and her mother, Sue, were fixtures in court. They lost two family members — Julian Bartley Sr., the consul general in the embassy in Nairobi, and Julian Bartley Jr., a college student working as an intern there.

"That was half of my family," Sue Bartley testified at the 2001 trial, in which four al-Qaida operatives were convicted and sentenced to life imprisonment.

Abdel-Bary, who had been granted refugee status in Britain, was arrested there in 1999 and extradited in 2012.

Prosecutors said he had been a trusted senior member of the London cell of Egyptian Islamic Jihad, a group led by Ayman al-Zawahri that effectively merged with al-Qaida.

At Abdel-Bary's 2015 sentencing, Edith Bartley told the court, "No family should have to go through our pain, but so many have to do it every day."

Abdel-Bary said he felt remorse. "If I could just do something to bring the victims back, your honor, I would have done it, but unfortunately I can't."