Police on Wednesday recovered from Haryana the car used by the killers of local BSP leader Deepak Bhardwaj in his farmhouse in New Delhi and picked up four men who are suspected to have provided illegal arms to the assailants.
About a dozen people were also questioned in connection with the murder of the 62-year-old politician and police were investigating whether any contract killers from Haryana's Sonepat is involved.
The Skoda car in which the assailants had come is suspected to have bore a fake registration number.
Police recovered the car from Haryana earlier in the day.
They also picked up four men who were suspected to have provided firearms to the trio who murdered Bhardwaj.
A senior police official said they were also talking to Bhardwaj's wife, who was staying separetely, and his sons to ascertain about a property dispute and whether he had any enemies.
The official said they have questioned about a dozen people in connection with the murder.
Police had on Tuesday released the CCTV footage of the attackers at the Nitesh Kunj farmhouse where the incident took place.
Investigators suspect the attackers were from Sonepat, going by the way in which the operation was carried out.
Bharadwaj, the richest candidate in the 2009 Lok Sabha polls with declared assets of over Rs 600 crore, was fired upon from point blank range by three men who fled after the incident.
He was gunned down by the trio who entered his farmhouse in Rajokri at 8:55 AM on the pretext of booking the place for a marriage, Delhi Police commissioner Neeraj Kumar had told reporters in New Delhi.
The assailants of the BSP leader, who was into education, hotel and real estate business and had declared assets worth over Rs 600 crore in 2009, had come in a dark grey Skoda car to the farmhouse.
He had suffered bullet injuries on his chest and back and slumped bleeding heavily. He was rushed to Army's Research and Referral Hospital near Dhaula Kuan in south Delhi where he succumbed to the injuries.