Two members of a notorious "Islamic State of Iraq and Syria" (ISIS) kidnapping cell dubbed the "Beatles" appeared in a US court by videolink on Wednesday (October 7th) after being flown to the US from Iraq to face charges of conspiring to murder four American hostages.

El Shafee Elsheikh, 32, and Alexanda Kotey, 36, are accused of involvement in the murders of American journalists James Foley and Steven Sotloff and relief workers Peter Kassig and Kayla Mueller.

The two former British nationals have been in the custody of US forces in Iraq since October 2019 after being captured in January 2018 by Syrian Kurdish forces.

They were brought to the US by FBI agents on Wednesday and the charges against them were read during an initial appearance in a federal court in Alexandria.

Wearing prison uniforms, handcuffs and face masks, the bearded ISIS members appeared on video from an undisclosed location in Virginia where they are being held.

Besides the deaths of the four Americans, Elsheikh and Kotey are also suspected of involvement in the killings of two Britons, Alan Henning and David Haines, and several other hostages including two Japanese nationals.

"Our message to other terrorists around the world is this -- if you harm Americans, you will face American arms on the battlefield or American law in our courtrooms," Attorney General Bill Barr said. "Either way, you will be pursued to the ends of the earth until justice is done."

'You will never escape justice'

The two ISIS members have been stripped of their UK nationality but the transfer to the US was made possible only after US authorities assured Britain they would not seek the death penalty.

Britain handed over evidence against the pair to the US authorities last month and a spokesman for Prime Minister Boris Johnson said Wednesday "we want justice to be done in this case".

The families of Foley, Kassig, Sotloff and Mueller welcomed the news that the two ISIS members had been brought to the US to face justice.

"James, Peter, Kayla and Steven were kidnapped, tortured, beaten, starved, and murdered by members of [ISIS] in Syria," the families said in a joint statement. "Now our families can pursue accountability for these crimes against our children in a US court."

"We are hopeful that the US government will finally be able to send the important message that if you harm Americans, you will never escape justice," they said. "And when you are caught, you will face the full power of American law."

'Physical and psychological violence'

The eight-count grand jury indictment against the pair charges them with various offenses including hostage-taking, conspiracy to commit murder and other charges.

If convicted, they face a maximum sentence of life in prison.

Kotey and Elsheikh's four-member ISIS cell was dubbed the "Beatles" by their captives due to their British accents.

They tortured and killed their victims, including by beheading, and ISIS released videos of the deaths for propaganda purposes.

According to the indictment, Kotey and Elsheikh were involved in abducting American, European and Japanese hostages in Syria from 2012 to 2015 along with two other British members of the "Beatles".

Alleged ringleader Mohamed Emwazi, known as "Jihadi John", was killed in a US airstrike in Syria in November 2015 while the fourth "Beatle", Aine Davis, is imprisoned in Turkey after being convicted on terrorism charges.

According to the US authorities, the London-born Kotey and the Sudanese-born Elsheikh travelled to Syria from Britain in 2012 after being radicalised in Britain.

They supervised detention facilities for hostages and allegedly co-ordinated ransom negotiations conducted by email, according to US authorities.

The pair also engaged in a "prolonged pattern of physical and psychological violence against hostages", they said, including beatings, mock executions and water-boarding.