A controversial female undertrial convict from Kerala Chief Minister Pinarayi Vijayan's home village, was found dead in a jail near Kannur on Friday, police said.
Soumya, 28, was arrested in April after she confessed to killing her parents and her nine-year-old daughter by poisoning them in a gap of four months this year.
After her arrest, she was kept at the Kannur Women's Jail, billed as a high security prison, where she was found hanging .
The body has been moved to a district hospital for autopsy.
Soumya, who had separated from her husband, had told interrogators that she killed her parents and daughter in order to live with her lover.
She was arrested after Mr Vijayan intervened in the murder case.
The police has started a probe into the alleged suicide.