Machendra Nath alias Pratibha Nand, who was carrying a bounty of Rs one lakh on his head, had allegedly taken a "contract" for Rs 5 crore to eliminate Bhardwaj, SP (City) Akash Tomar said.
He had been absconding since the killing, Tomar added. A foreign-made pistol has also been seized from his possession.
The Bahujan Samaj Party leader was gunned down by contract killers Sunil Mann alias Sonu and Purushottam Rana alias Monu at his sprawling farmhouse in south Delhi. He was one of the richest candidates in the 2009 Lok Sabha election, having declared assets worth Rs 600 crore.
The six arrested individuals in the case so far are the BSP leader's son Nitesh Bhardwaj, Shehrawat, a lawyer-cum- property dealer, Rana and Mann, Amit, the driver of the car used by the "killers", and Rakesh, the car owner.
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