The police in Kerala’s Kannur district arrested a woman on Tuesday night for allegedly murdering her parents and her nine-year-old daughter by poisoning them in small doses over several months, The News Minute reported.

The police claimed that 28-year-old Soumya, a resident of Padannakkara locality in the town of Pinarayi, confessed after being questioned for 13 hours. “We have recorded the arrest of Soumya after she confessed to the killings,” district police chief Siva Vikram G said. “But we are not able to tell her motive.”

The police questioned her at a state-run hospital near Kannur, where she has been admitted for nausea and indigestion.

Soumya’s daughter died on January 31, her mother V Kamala on March 7, and her father died on April 13. All of them reportedly had the same symptoms before they died. The police, acting on a complaint filed by a relative, conducted an autopsy of the bodies of Soumya’s parents, and reportedly detected rat poison in their viscera.

A court then ordered the police to exhume the daughter’s body. A forensic surgeon from the medical college in Pariyaram conducted the initial autopsy of her body, and sent the remains to a forensic laboratory in Thiruvananthapuram for a detailed examination.

The Crime Branch is conducting the investigation in the case on Chief Minister Pinarayi Vijayan’s order, Manorama reported.