A 25-year-old person hailing from Khagaria district has been held for the murder of an elderly couple and their son in New Delhi's Sarai Rohilla area last week.

Deputy commissioner of police (north) Madhur Verma told PTI on Monday that the accused has been identified as 25-year-old Mithlesh Mehto, a former tenant of the victims, who had left the accommodation two weeks before the crime.

Officers said Mehto allegedly held a grudge against the couple's son, 30-year-old Rakesh, who had asked the youth for a loan and thrashed him after being refused. Police said Mehto went to his village in Khagaria after the incident before returning to Delhi on September 22.

He went to his former landlord's house the next night, pretending to work at a reconciliation. During the meeting, Mehto allegedly offered Rakesh a sedative-laced soft drink. Once Rakesh dozed off, Mehto tied his limbs with a nylon rope and allegedly slit his throat, then went downstairs and did the same to his parents.

He also ransacked the room and fled with some jewellery and cellphones when he was spotted by two neighbours of the family.