Madhya Pradesh chief minister Kamal Nath has stressed the need for a “full investigation” into the attempt to destabilise his government, hinting at action against those responsible for keeping Congress MLAs captive in Bangalore.

Taking the unusual step of writing a letter to the governor on the issue, the chief minister directly blamed the BJP for the crisis and iterated his resolve to fight back.

“In these disturbing circumstances, the very edifice of democracy is in danger. Trust of a transparent democratic process seems lost. It merits full investigation and inquiry so that persons responsible for derailing the democratic institutional process are exposed and punished,” Kamal Nath wrote.

Sources said the police had already started the investigations and action would follow soon.

The chief minister’s letter said: “Our commitment to the democratic institutional process is unwavering. We expect the inquiry and investigation on the resignation letters submitted by the BJP allegedly of the captive Congress MLAs is acted upon and completed early.”

In Bangalore, Congress MLA Jitu Patwari and Karnataka unit chief D.K. Shivakumar accompanied Narayan Chaudhary, father of MLA Manoj Chaudhary, to the additional director-general of police to lodge a complaint against the captivity of MLAs. The father sought permission to meet his son.

After meeting the governor, Kamal Nath said: “We are ready for a floor test. That will happen. But free all the captive MLAs first. Bring them before the media.”

The chief minister was suggesting that they were being held hostage against their will. The Congress has been claiming that being loyal to Jyotiraditya Scindia in the factional fight and joining the BJP was entirely different propositions.

The chief minister requested the governor to use his good offices with the Union home minister to ensure the release of the MLAs held in captivity in Karnataka. The southern state is now ruled by the BJP.

The letter said: “The BJP on March 8 arranged three chartered aircraft to whisk away 19 MLAs of the Congress to Bengaluru. Since then these 19 MLAs, of whom six are cabinet ministers, are incommunicado in a resort arranged by the BJP. Nobody is allowed access and/or any sort of communication with the 19 captive MLAs. To utter shock, senior leaders of BJP reached the Speaker’s residence at about 5.30pm on March 10 to handover 19 resignation letters allegedly of these Congress MLAs.”

Contending that this demonstrated the complicity of the BJP in the entire conspiracy, Kamal Nath’s letter added: “It raises questions of constitutional propriety and legislative procedure and transparency. The submission smacks of dehors (outside the scope of) the provisions of Constitution and the legislative rules in force for submission and acceptance of resignations of MLAs.”

The chief minister recommended to the governor the removal of six ministers, which was accepted. Now that the ministers have lost their jobs, the Congress is working on the remaining MLAs who could be lured with ministerial berths.

Pressure will be mounted on them after they reach Bhopal to explain their stance before the Speaker.