A 26-year-old woman and her boyfriend smothered her parents to death in their sleep, stuffed their bodies in suitcases, and dumped them in a drain in outer Delhi’s Nihal Vihar — one by one over a period of 10 days — in a bid to grab their property, police said on Monday.

The woman, Davinder Kaur alias Sonia, drugged and killed her father, 54-year-old Gurmeet Singh on February 21, and then used the same modus operandi to kill her mother, 46-year-old Jageer Kaur, on March 2, according to the deputy commissioner of police (outer district) Seju P Kuruvilla.

The murders were committed in their home in Chander Vihar, where the couple lived with Sonia. The bodies were recovered from the drain, about five kilometres away, during an eight-hour-long search over last Friday and Saturday.

Police said the woman managed to mislead her relatives and neighbours for 17 days, until investigations began suspecting her after speaking to her estranged husband and other people in the vicinity. Finally, Sonia’s “contradictory statements” and “odd behaviour” gave her away.

The woman, who has a son and a daughter, has been separated from her husband since December 2017.

Police said she was in a relationship with Prince Dixit alias Vikram, a 29-year-old event manager from Lucknow who was her accomplice in the crimes, for the past year. Sonia and Vikram, who were arrested on Sunday, took the help of two other people — both Vikram’s friends from Lucknow — who are yet to be arrested.

Sonia’s father was a tall and burly man who returned from Dubai last year after years in the furniture business. One of his sons separated from the family after he got married. Another son works as a chef in Kuwait and a daughter lives with her relatives.

The family’s one-storey house, constructed over a 1,100 sq ft plot, was the property Sonia allegedly hoped to grab after killing her parents, the DCP said.

She killed her father while her mother was away at her maternal home in Punjab for the post-funeral ceremonies of her grandmother, who died on March 10. “Sonia and Vikram called two men from Lucknow to help them with the crime. Sonia mixed sleeping pills in her father’s tea. The four of them then smothered him,” said the DCP.

The same night, they allegedly tied the father’s limbs with his turban, stuffed the body in a green suitcase, loaded it on a motorcycle, and dumped it in a drain near village Sayed in Nangloi.

“The family hardly interacted with neighbours, so we didn’t realise about Gurmeet’s disappearance,” said a local shopkeeper. Police said that Sonia did not report her father’s disappearance to the police.

When, Sonia’s mother returned from Punjab on the evening of March 2, Sonia, Vikram and one of their accomplices killed and dumped the mother in the same drain, using the same modus operandi, said the DCP.

This time, Sonia alerted her relatives after which a missing complaint was filed at Nihal Vihar police station.

The first body to be recovered was that of Sonia’s mother that was found by a passerby in a maroon suitcase around 4.30pm on Friday.

“I was passing by and saw police and a crowd. When I got to know that a body was found, I alerted the police that my in-laws had gone missing. The body turned out to be that of my mother-in-law. I urged the police to search the nearby areas as my father-in-law too had been missing,” said Sonia’s husband, Karun Sharma, who is a regional sales manager with a pharmaceutical firm.

“We continued the search and found the other suitcase in another part of the same drain at 12.30am on Saturday. The body of Sonia’s father had greatly decomposed,” said the DCP.

Sonia and Vikram have been booked for murder. Forensic examinations to gather evidence against the accused persons is underway, police said.

First Published: Mar 11, 2019 22:03 IST