LONDON — Former Islamic State hostages and families of the group’s victims are urging Britain and the United States to put two recently captured extremists on trial, arguing that denying them justice will fuel the hatred and violence they supported.

French journalist Nicolas Henin, who was held by the men and their comrades for 10 months, said he wants justice after the arrest of the two Britons, who were part of the notorious cell dubbed “The Beatles.” Henin said the men should be tried in the U.K., not shipped to Guantanamo Bay, because revenge will just breed more violence.

“What I’m looking for is justice and Guantanamo is a denial of justice,” he said Friday. “There hasn’t been a single trial in 16 years there … Guantanamo was actually one of the reasons for their engagement in extremism, in jihad. So if we perpetrate this kind of atrocity, we are not helping our quest for justice.”

U.S. officials have confirmed that El Shafee Elsheikh and Alexanda Amon Kotey, who grew up in London before traveling to the Middle East to join the Islamic State, were captured in early January in eastern Syria.

U.S. officials have interrogated the men, who were part of the IS cell that captured, tortured and beheaded more than two dozen hostages, including American journalists James Foley and Steven Sotloff, and American aid worker Peter Kassig.

The capture of Elsheikh and Kotey could yield precious intelligence about what happened to those fighters as IS was defeated on the battlefield, and information about their hostages, said Shiraz Maher, a senior research fellow at the International Center for the Study of Radicalization and Political Violence at King’s College London.

“It’s hugely significant for a lot of the Western countries who had hostages who were captured by Islamic State,” he said. “I think it demonstrates that there remain high-value, significant players at large.”

Maher agreed that Elsheikh and Kotey should be brought to trial because it will bring closure to their victims and send a message to anyone who considers joining such extremist groups.

“These guys had an absolute sense of their own invincibility,” he said. “They were filled with euphoria. (Trials) will make people think twice.”

The two are believed to be linked to Mohammed Emwazi, the masked British insurgent known as Jihadi John who appeared in several videos that showed the beheading of Western hostages. The cell was nicknamed “The Beatles” because all four members had English accents.

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