Syrian gang rape victim who fled to Germany after her ordeal is stabbed to death 'in honour killing ordered by her own mother because she was seen as unclean after her sex assault'
- Victim, named only as Rokstan M, 20, found in a shallow grave on allotment
- Detectives believe she was stabbed to death by her father and two brothers
- She fled to Germany two years ago after being raped by three men in Syria
- Once said: 'My mother and brothers mistreat me and say I deserve to die'
- Mother denies ordering killing, saying: 'I had nothing to do with her death'