On June 5th, eight Americans were quietly flown home from the former ISIS caliphate in Syria. The two women and six minors, whose identities were not disclosed, are now being resettled at unnamed locations with help from the U.S. government. They are not the first citizens of the Islamic State to return. Four other Americans—three men and a woman—await trials on various charges of aiding or abetting the world’s most notorious terrorist group. Three more agreed to plea deals; one has already served time and been released. A lone American opted for a trial and was sentenced to twenty years, although his case is under appeal.

They won’t be the last returnees, either. For months, the F.B.I. has been searching for Americans among the two thousand foreign fighters who surrendered or were captured on the battlefield. (After five years of war, the Islamic State finally collapsed on March 23th.) Another twenty or so Americans, including half a dozen fighters, have been identified, U.S. officials told me. Most were in prisons run by the Kurdish-led militia that defeated ISIS or detention camps for women and children. The U.S. intention is to bring them all home—eventually.

So far, the handling of returnees has been far different from what Donald Trump promised during the Presidential campaign. In 2016, Trump vowed to use Guantánamo Bay—the prison camp opened in Cuba to house enemy combatants from the Afghanistan war—for captured ISIS fighters. “We’re going to load it up with bad dudes,” he said. In his first State of the Union speech, in 2018, he announced a new executive order to keep Gitmo open, reversing President Barack Obama’s policy. “Terrorists who do things like place bombs in civilian hospitals are evil,” Trump said. “When possible, we have no choice but to annihilate them. When necessary, we must be able to detain and question them. But we must be clear: terrorists are not merely criminals, they are unlawful enemy combatants.”

Instead, the Justice Department has opted to try ISIS returnees in U.S. courts and even to release or resettle some of them. But the process is still in its early stages. “The United States is committed to taking responsibility for its citizens who attempt to travel or did travel to support ISIS,” Marc Raimondi, the Justice Department spokesman, told me last week, in an e-mail. “We have prosecuted over 100 cases against individuals who tried to travel to support ISIS and have brought charges against several who have returned, including as recently as earlier this year.”

Other Americans may still be underground with ISIS cells in Syria or Iraq, U.S. officials concede. Just identifying U.S. citizens has been tricky. Most foreigners took noms de guerre. Some assumed names denoting nationality—such as al-Amriki, or “the American”—as new surnames. Those could be misleading, however. One sixteen-year-old fighter—Soulay Noah Su, who took the name Abu Souleiman al-Amriki—turned out to be from Trinidad and Tobago. An unknown number of Americans—possibly even the majority—may have been killed on the battlefield.

The Americans who travelled to the Islamic State fit no single type. So far, the returnees have included a substitute teacher from Texas, a Baptist mother of four from Indiana, a former student from Columbia University, and an F.B.I. translator who married the terrorist she was spying on. Most were born in the United States; they were not immigrants. They’re geographically diverse—from Texas, California, Michigan, Virginia, New York, and Indiana. The adults have ranged in age from mid-twenties to mid-fifties, according to George Washington University’s Program on Extremism. The children of American ISIS members include teen-agers who accompanied their parents when they left the United States and toddlers who were born in the Islamic State, according to U.S. officials and lawyers defending ISIS returnees.

Deciding the fate of the Islamic State’s former citizens is a legal and moral minefield. National-security interests can conflict with individual rights. Their cases raise unanswered questions about the government’s authority to invoke wartime powers against the Islamic State without congressional authorization. The timing of returns so far suggests that the Justice Department may not want to repatriate ISIS members until it has sufficient evidence to indict them immediately upon arrival. American citizens cannot be jailed indefinitely at home without violating their constitutional rights. Yet simply figuring out what each individual did in the caliphate—a “state” that no longer physically exists—is a time-consuming challenge. The main witnesses may be other citizens of the Islamic State.

Last year, the United States opted to release a suspected ISIS member after holding him, without trial, for thirteen months. He had been captured by the U.S.-backed Syrian Democratic Forces, in 2017, turned over to U.S. forces, and detained at a U.S. base in Iraq. He was cited in court filings only as “John Doe.” The Times identified him as Abdulrahman Ahmad Alsheikh, a dual U.S.-Saudi citizen born in the U.S. and last resident in Louisiana. In October, with a legal challenge to his open-ended detention still pending, the U.S. opted to free him; he was turned over to Bahrain. His U.S. passport was revoked, but his lawyer claimed he bargained to keep his citizenship.

The recent return of eight Americans has generated new questions about U.S. metrics for judging affiliation with a terrorist group, notably by female returnees. The U.S. is helping resettle the two women repatriated last week. But, last year, Samantha Elhassani (née Sally), a Baptist mother from Elkhart, Indiana, who was married to a Muslim American, was charged when she was repatriated. The first indictment alleged that she had provided “material support and resources” for Islamic State personnel, namely her husband and his brother, by transferring money out of the United States and obtaining rifle scopes and binoculars. A subsequent indictment charged her with conspiring to aid ISIS personnel with the full knowledge that the group was a designated terrorist organization. The charges carry prison sentences of up to forty years. She has pleaded not guilty.

The Elhassani case is full of bizarre twists and disputed facts. In 2015, she went with her second husband, Moussa, and two children to Syria. They had two more children in Raqqa, the capital of the Islamic State. Moussa was killed in a drone strike, in 2017. She and her four children fled Raqqa as it fell, the same year; they were detained by a U.S.-backed militia. She was questioned by the F.B.I. and asked to be repatriated. She was flown home, charged, and jailed, and her children placed with Indiana social services.

At her bond hearing, in December, her defense counsel, Thomas Durkin, disclosed that that Elhassani had been a paid F.B.I. informant for two years before she went to Syria. (She had provided serial numbers of cell phones being shipped to Yemen by a company owned by her husband’s family.) “I find it incredibly ironic that somebody who coöperated with the F.B.I. for two years, the F.B.I. took under their wing, and, I assume, believed everything she said, all of a sudden now turns the tables, was now unreliable,” Durkin told the court. He also claimed that Elhassani acted “under the direction of her husband, who is unquestionably crazy and unquestionably an abuser.” She had believed the family was going to Morocco; he duped her after they arrived in Istanbul. Durkin said she had not known her husband’s intent when she carried tens of thousands of dollars to Hong Kong and picked up the small amount of equipment purchased by her husband before he took them to Syria.

One of the most damning pieces of evidence is an ISIS propaganda video that prosecutors say Elhassani filmed of her ten-year-old son, Matthew, renamed Yusuf in the caliphate. “My message to President Trump, the puppet of the Jews: Allah has promised us victory and he’s promised you defeat,” the child said in the video. “It’s not going to end in Raqqa or Mosul. It’s going to end in your lands. So get ready. The fighting has just begun.” The boy then loaded a rifle and peered through its scope.