After the gruesome act, Kanhaiya called up police and confessed to his crime. A team was sent to the spot and he was arrested immediately, police said.
"Both the girl and the woman were rushed to a hospital, where one was declared brought dead and the other was admitted with multiple injuries," DCP (northwest) Vijay Singh said, adding Kanhaiya has been booked for murder and attempt to murder.
Yesterday night, Kanhaiya returned home late and had a heated argument with his wife, following which he took the girl at knifepoint and started questioning his wife about her conduct, he said.
At one point, he broke down and suddenly slit the child's throat. Then he went to his wife, who was horrified by what she had just witnessed, and attacked her until she collapsed.
He and his family had migrated from Chhapra in Bihar a few years ago. The family lived at a rented apartment in Adarsh Nagar area.