Here are 10 developments in the story:
Audio clips purportedly of phone conversations involving Ajit Jogi, former Chief Minister and his son Amit Jogi were highlighted by the Indian Express newspaper.
The conversations suggest that the Jogis took money while striking a deal for a Congress candidate to withdraw from a by-poll contest last year. NDTV cannot vouch for their authenticity.
"We will file a case against the publication and the correspondent who did this story. This is the fake conspiracy," Ajit Jogi, 69, said, alleging that the tapes were doctored.
The voice purportedly of Amit Jogi appears to be bargaining over the money to be offered to the candidate, Manturam Pawar, to withdraw from the contest. Mr Pawar pulled out 15 days before the election and the BJP candidate won.
One conversation is purportedly between Ajit Jogi, his son and Chief Minister Raman Singh's son-in-law.
The Congress candidate apparently says in one of the conversations that he would have won easily but withdrew his candidature because he trusted the Jogis. He joined the BJP earlier this year.
The BJP's Bhojraj Nag had a virtual walkover in the poll because along with the Congress candidate, 10 independents also quit the race.
In the 2013 Chhattisgarh polls, the Congress won eight of 12 seats in Bastar. Manturam Pawar lost his seat then by just around 5,000 votes. Had he won the bypolls, it would have been a big boost for the Congress.
After the Congress candidate dropped out suddenly, Ajit Jogi had seized the chance to attack the state party chief, his rival.
When the state of Chhattisgarh was carved out of Madhya Pradesh in 2000, Ajit Jogi, a former IAS officer, became its first chief minister. He lost last year's national election by a few hundred votes.
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