While the couple, identified as Jameel (42) and Ruby (38), were declared brought dead at a hospital, the child is battling for life after one of his arms and a leg was chopped off, Superintendent of Police Ram Badan Singh said.
During interrogation, Kajiyana resident Naushad said his elder brother was an alcoholic and due to this there were frequent disputes in the house. On Sunday evening Jameel came to the house and started urinating in an open drain to which their mother opposed.
Jameel started arguing with their mother and tried to attack her with a sharp-edged weapon used for cutting meat. Seeing this, Ruby rushed to intervene with the child, Mohammad Ali, in her lap, Naushad told the police.
Following this, Naushad said he intervened in the dispute during which his brother and sister-in-law were killed and the child was injured.
Citing the post-mortem report, the SP said, 'There were eight injury marks using the butcher's knife on the bodies of the mother and the child. A case has been registered against Naushad, and he was arrested on Monday evening, when he was trying to escape from the district along with his mother.'
Inputs from PTI