A Syrian doctor living in Germany is being investigated on suspicion of carrying out crimes against humanity at a military hospital in the war-torn country, a report in Spiegel magazine Friday said.

Federal prosecutors suspect the man of beating and torturing men arrested by the Syrian regime while working as a doctor in the hospital in the city of Homs, the report said.

The federal prosecutor's office in the southwestern city of Karlsruhe declined to comment when approached by AFP.

The man, identified only as Hafiz A., reportedly moved to Germany in 2015 and now lives and works as a doctor in the state of Hesse.

Two witnesses told investigators that the man and a colleague withheld medication from an epileptic patient and then forced him to take a pill that caused his condition to rapidly deteriorate. The doctor and other men finally beat the patient to death, the witnesses have alleged. His family is said to have found his body the next day with bloody wounds on his face and holes in his skull. Two further witnesses, former doctors at the military hospital, said the man had also intentionally operated on an opponent of the regime without anaesthetic. He is also alleged to have poured alcohol onto another man's genitals and then set him on fire.