A former London postman who joined the Isis terror group in Syria has been charged with taking part in the execution of six prisoners after footage of the murders emerged.
German-born Harry Sarfo, 28, is already serving a three-year-sentence in Germany on terror offences.
He was further charged with six counts of murder and violating human rights law at a specialist state security court in Hamburg, the federal public prosecutor's office said on Wednesday, 19 July.
The new charges were brought after a video obtained by the Washington Post from a source inside Isis shows a man appearing to be Sarfo being involved in the executions.
"In mid-June 2015 the so-called Islamic State had six prisoners executed on Palmyra's market square," a spokesperson for the prosecutor's office told the Independent.
"Sarfo belonged to the six-member squad that carried out the execution and he was armed with a pistol. Together with other members of his group, he guarded the prisoners and prevented them from escaping.
"During the shooting, he stopped at the side of the road so as not to be hit by a bullet himself. From there, he took aim and fired at the bodies lying on the ground," the spokesperson continued.
Five of the men who were killed were believed to be members of the Syrian Army. The sixth man was thought to be an Islamic preacher condemned by Isis, which persecutes those who do not abide by the strict rules imposed throughout its occupied territories.
The footage seems to contradict Sarfo's claims that he never fought for the group during his three months with the militants.
In an interview with the Independent last year, Sarfo described Isis as "the path to hell" and warned Muslims who may be considering joining the terror group against doing so.
Sarfo, who moved to London as a teenager, joined Isis in 2015, after being radicalised online.
However, after a few months, the former Royal Mail employee decided he no longer wanted to be an Isis fighter. He escaped from Raqqa - Isis's strongholds in Syria – and made his way back to Germany, where he stood trial on terrorism charges.
Isis used to control large swathes of territory in Syria and Iraq but it is progressively losing territories following joint offensives in both countries.
Raqqa has witnessed intensified fighting in recent weeks, after the Syrian Democratic Forces (SDF) – an alliance of Kurdish and Arab militias supported by a US-led coalition – started a campaign to recapture Raqqa from Isis. The group captured the city in 2014, turning it into the capital of its self-declared "Caliphate".