The family ran a grocery shop and plywood business out of their home in Burari.
Police said the body of an elderly woman was lying on the floor, while the others were found hanging. The Delhi Police has sent a team to the spot, and an investigation is underway.
Ward commissioner Rekha Sinha informed that the family belonged to a person named Lalit and those deceased include him along with his mother, sister, wife, children, brother, brother's wife and his children.
Police said the quarrel between the two groups dates back to 2013.More news: Kawhi reaches out to LeBron about teaming up, but where?
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According to reports, the family shop used to be open from 6AM in the morning. The incident came to light when a neighbour went to the house to call the family head with whom he go for morning walk.
One of the dead was 75-years-old while three others were minors. The entire area has been cordoned off.
Police is yet to give out further details of the case.
Police say they are investigating all angles, including a murder-suicide pact.