The incident was reported from Nihal Vihar last night and the deceased have been identified as Krishna Devi and her granddaughter Nainsi.
Police suspect the involvement of their relative Dinesh and his friend Vikas in the murder.
Devi's son and his wife Sonia had gone to Kurukshetra when the incident took place.
The incident took place last night at their residence at Hatia Bagh Nagar in Nihal Vihar.
Dinesh, Satpal's cousin, and his friend Vikas came to their house and allegedly strangled Devi and Nainsi.
Satpal had given Dinesh and Vikas Rs 3.5 lakh as loan and a few days ago the duo had a dispute with Satpal over this.
They were allegedly nurturing a grudge against Satpal, a senior police official said.
However, the official said it is yet to be established whether Dinesh and Vikas came to Satpal's house with the intention to kill them.
"Prima facie, it appears that they did not bring any kind of weapon with them. Whether the murders were committed on the spur of the moment, would be clear after their arrests," the official said.
New Delhi: A 70-year-old lady and her six-year-old granddaughter were strangled allegedly by a relative and his friend in west Delhi following a financial dispute, police said on Saturday.
First Published: Saturday, April 02, 2011, 21:00