Acting on a tip off by close relatives of the victims of the Parasbigha massacre in Bihar about the movement of Singh, a police team of women unit raided the flat and arrested Singh who was hiding in a heap of clothes in a room, Senior Superintendent of Police Manu Maharaj told reporters.
Singh was convicted by the Supreme Court in 1996.
The police had earlier tried to arrest him from Delhi, Uttar Pradesh, Jharkhand and Assam, but he had managed to give a slip on all occasions in the past and stayed underground, Maharaj said.
Maharaj said that Singh's interest in real estate and his desire to spend times with his son Gaurav Singh proved to be his undoing in the end as the long arms of law finally managed to catch him.
Armed assailants killed 13 people at Parasbigha in 1980 following a land dispute between landlords and cultivators.