A Facebook prank on a relative by two young women posing as a fictitious lover went horribly wrong, setting off events that have claimed three lives including that of a newborn, Kerala police have said.

What unravelled the bizarre chain of events was the police’s doggedness in carrying out DNA tests across a neighbourhood to solve the death of an abandoned baby — something almost unheard-of in the country.

The newborn had been discovered in a pile of dried leaves near a temple in Kalluvathukkal town, Kollam district, around 6.30am on January 5, its cries attracting the attention of a few people. They informed the police, who took the baby to a hospital in Thiruvananthapuram. But the infant died the same day, the post-mortem revealing it had choked on bits of dried leaves that had got into its lungs.

Instead of closing the case in a country where unclaimed bodies are almost a feature of everyday life, the police obtained a magistrate’s permission and embarked on a mission of DNA-matching across the Uzhayikkode neighbourhood where the baby had been found.

After eight DNA tests they eventually zeroed in on Reshma, 24, arresting her on June 22 for the alleged murder of her infant son.

Her purported confession revealed a macabre tale. According to the police, Reshma said she had abandoned her baby since she planned to join her “lover” who did not want to take care of another man’s child.

She purportedly said she had chatted with her “lover”, who had introduced himself as Ananthu, on Facebook for over a year but never met him or spoke to him over the phone.

Reshma’s husband Vishnu, who had gone to the Gulf to work just four months earlier, rushed back after learning of his wife’s arrest. Strangely, neither he nor his mother, with whom Reshma lived, seemed to have any idea about Reshma’s pregnancy or the childbirth.

“She did not tell her husband or even her own family that she was pregnant,” assistant commissioner of police Y. Nizamuddin told reporters.

Police sources said Reshma had told the investigators she wore loose-fitting clothes to hide her bump and never consulted a gynaecologist.

Reshma allegedly confessed that she had delivered the baby in a bathroom outside the house and immediately abandoned it, fulfilling a precondition to join her “lover”.

Police sources said Reshma then informed her “lover” about having abandoned the baby, following which the alleged pranksters cut off Facebook contact with her and lay low.

However, the police found out that Reshma had used a mobile SIM card that belonged to Arya, 23, wife of Vishnu’s brother, to access Facebook. On June 24, the investigators summoned Arya to appear before them the same afternoon.

She never came. The police learnt that Arya, mother of a three-year-old girl, and Vishnu’s niece Greeshma, 22, were missing.

Officers launched a search after security-camera footage showed the two women walking towards the Ithikkara river. Their bodies were fished out on June 25. Arya, Greeshma and and Reshma lived within 2km of one another.

Arya left behind a purported suicide note saying: “Didn’t want to cheat anyone knowingly. Didn’t realise she (possibly Reshma) is such a cheat…. Just can’t handle police arresting us for murdering an infant. Everyone should pardon us.”

Among those interrogated over the double suicide was a male friend of Greeshma who said she had told him about the prank.

“Greeshma told her boyfriend that their prank had gone out of hand,” Nizamuddin said.

By Sunday evening, a local news website had reported a first-time director’s plans to shoot a Malayalam movie, to be titled One Day Mirror, based on the tragedy. Filming is likely to begin in October.