Another family member, Sunita, was found lying unconscious and has been hospitalised, he added.
The murders appear to have taken place on Friday as all the blood had dried up. All of them including the toddler were brutally stabbed to death, Dak said.
According to preliminary investigation, Dharmendra was allegedly engaged in flesh trade and was living at a rented house in Mahadev Nagar.
Police is suspecting the hand of someone known behind the murders who probably had rivalry with Sindhi, Dak said, adding that the involvement of more than one person had not been ruled out.
"We have found foot marks in the house. The murderers have tried to make the incident look like a loot as the house appeared to be ransacked but nothing was found missing, he said.
Dak said the cause of the murder was yet to be ascertained but it is believed that his trade might have some bearing on his and his family's murder.
"We are investigating the matter and are awaiting the FSL report of the incident," he said.