Namdhari's five-day custody will end on Thursday and police will produce him before court.
A senior police official said they will seek further custody of Namdhari and with his help, they hope to collect more evidence.
Sources said police is also planning to question Narender Ahlawat, the manager of Ponty Chadha who was injured in the November 17 shootout at Chattarpur in which Ponty and his brother Hardeep were killed.
"He is recuperating and we are planning to record his statement soon," the official said.
Police had so far questioned over 100 people in connection with the case and have arrested seven persons directly or indirectly involved in the case.
Investigators had taken the help of forensic experts to reconstruct the killing of liquor baron Ponty and his brother as investigators claimed to have found discrepancies in statements made by Namdhari and his PSO.
The experts from CFSL, which is under CBI, went to the Chattarpur farmhouse on Tuesday along with police officials where they reconstructed the scene.
Delhi Police had alleged that Namdhari opened fire at Hardeep, a charge denied by Namdhari.
Investigators also suspect that Namdhari tampered with his gun. Namdhari's son, a relative and driver, who allegedly helped him in tampering with the gun, are absconding, police said.