The girl, identified only as Sonam, and her boyfriend, identified only as Naveen, 20, have been charged with murder in the Sept. 14 deaths of Sonam's mother, father, grandmother and four other relatives, The Times of London reported Tuesday.
Sonam allegedly told police she laced the family meal with a sedative and after they fell asleep, she and her boyfriend strangled them in their home in the village of Kabular, about 50 miles from Delhi, The Times reported.
The family allegedly would not let the couple marry because they belonged to the same gotra, a group descended from a common ancestor.
Kirti Singh, a spokeswoman for the All India Democratic Women's
Association, said prosecutors should consider whether the couple had been threatened by Sonam's family.
Hundreds of young people are killed annually in India for violating marriage traditions, Singh said.