JIHADISTS returning to Germany from fighting with the Islamic State group in Syria and Iraq have revealed the extent of the terrorist militia’s brutality against its own members, according to a newspaper article.

Some 200 German jihadists have returned from the fighting and one in five of them is co-operating with German security services and giving details of the time spent with IS, the Sueddeutsche Zeitung reported on Saturday.

Many of the returning fighters speak of a climate of fear, mistrust and mercilessness. One spoke of being taken to a “slaughterhouse” because he refused to hand over his passport. The walls and floor were covered in blood.

He also told of a headless corpse being tossed into his sleeping quarters.

Suspected informants are tortured, shot or beheaded, the report said.

One returning fighter spoke of a newcomer being executed merely because he had hidden his mobile phone. The terrorists are afraid that US drones can lock onto the positioning data of mobile phones.

There were also reports that fighters who tried to leave the country without the written permission of an emir were shot.

Some fighters spoke of brutal tests of their courage, including being ordered to murder people just to show that they could follow orders from IS.

Some 50 fighters have returned to the German state of North Rhine Westphalia. The authorities there are most concerned about the brutalised, battle-hardened jihadists among them. They estimate around 10 men belong to this group. The remaining fighters are traumatised or disillusioned, according to the report.