The body of the deceased, identified as Sarita, bore several stab wounds, they said, hinting at an extra-marital affair between the woman and her neighbour Ravinder, who along with his family was found missing.
Sarita, a mother of five, was missing since yesterday evening and her husband Suraj had lodged a missing complaint.
Ravinder was staying with his wife and six-year-old son in a rented house of one Satpal in the locality, they said.
Today morning Satpal discovered Sarita's body from the septic tank after his wife found blood stains inside the toilet, police said.