The 28-year-old accused identified as Shahnawaz was upset over her sister having an affair with a boy of different community. He had been pressurising her for ending the relationship for past few months, police said.
Yesterday, the brother-sister duo had an argument over the issue following which the accused first locked the family members in a room and then strangulated the victim using a scarf, they said.
Shahnawaz, then surrendered himself before police.