The police on Monday arrested an 18-year-old for killing his sister who refused to marry a relative of theirs.
Her father, and the brother had told neighbours that she had consumed poison and died on way to hospital. They cremated the body.
The incident, however, came to light when villagers informed the police on Sunday of a quarrel that took place at their house.
During inquiry, it was found that she was being forced into a marriage with a 33-year-old lorry driver.
She had twice informed the Childline about the marriage.
On December 14, the girl informed Childline that she was being harassed and went to their office in Namakkal.
She was produced before the Child Welfare Committee, and was lodged at home.
On December 15, her relatives came there and told her that her father had attempted suicide, and took her home.
On December 17, an altercation broke out between she and her brother regarding marriage.
He beat her and strangulated her to death in the afternoon.
They kept the body in the house till evening and took her in an an ambulance stating that she consumed poison. Later, they returned home stating that she died on the way to hospital and cremated the body.
