- Konika Dhar hopes the London-accented man on an ISIS video is not her brother Sid
- "There's an element of guilt.... Why could I not stop it?" she wonders
- She remembers him refusing to eat food prepared by his mother after converting
London (CNN)When ISIS released its latest propaganda video last week, all eyes were on the militant group's new poster boy. Clad in black, wielding a handgun and his face hidden by a ski mask, he issued threats in a distinctive London accent.