"Whatever evidence is on record is sufficient to name Bansal as an accused.
"Rather surprisingly, he has been made a prosecution witness by CBI," said Satya Pal Jain, former BJP MP and the chairman of the party's national committee on legal and Election Commission issues.
The alleged scam came to light after CBI on May 3 raided the office and residence here of Bansal's nephew Vijay Singla who was caught red-handed with an amount of Rs 90 lakh.
Bansal had quit as minister in the wake of the scam. Ten persons have so far been arrested in connection with the case.
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Reading out some of the call details of one of the accused, Jain said that on May 2, Mahesh Kumar had talked on the land-line phone of a senior Delhi-based Congress leader.
He said that the name of the same leader had figured a number of times in conversations the accused had held with others involved in the case over the course of several days.
"The conversations between the various accused (persons) clearly indicate that Bansal was in the loop... He cannot distance himself from the scandal," Jain said.