Leader of Opposition Siddaramaiah blamed the Karnataka BJP for his death.
A contractor, who had accused the Karnataka Rural Development and Panchayat Raj Minister KS Eshwarappa's associates of demanding a 40 per cent commission for a contract, was found dead at a private lodge in Udupi this morning.
Santosh Patil reportedly sent messages to the media and his friends early this morning, saying that he was going to end his life and alleged that Mr Eshwarappa was responsible for his death.
In his purported suicide note, Mr Patil urged Prime Minister Narendra Modi, Karnataka Chief Minister Basavaraj Bommai and senior BJP leader BS Yeddyurappa to help his wife and kids after his death.
"RDPR minister KS Eshwarappa is solely responsible for my death. I am taking this decision, keeping my aspirations aside. I request with folded hands to our prime minister, chief minister, our beloved lingayat leader BSY and everybody else to extend a helping hand to my wife and kids," he wrote.
His friends were staying in a room next to his, the police said, adding that the incident was being probed.
Reacting to Mr Patil's death, Mr Eshwarappa said he learned about his suicide through media and reiterated that he did not know him.
He turned down the demand of the opposition Congress seeking his resignation over the contractor's death.
"There is no question of resigning. We have to wait for the verdict of the court in the case I had filed against Santosh Patil. I make it very clear that I am not at fault anywhere," Mr Eshwarappa said.
Mr Eshwarappa last month denied the bribery charges after Mr Patil wrote a letter to Union Minister Giriraj Singh, accusing his associates of demanding a 40 per cent commission in the Rs 4 crore work he had carried out in Rural Development and Panchayat Raj department.
The Congress renewed its attack on the BJP and demanded an FIR against the Karnataka minister and an independent probe into the incident.
Senior Congress leader Rahul Gandhi accused PM Modi and the Karnataka Chief Minister of being complicit in the contractor's death, saying that the Mr Patil's pleas to them went unanswered.
"BJP's 40% Commission Government in Karnataka has claimed the life of their own Karyakarta. The victim's pleas to the PM went unanswered. The PM and CM are complicit. #BJPCorruptionFiles (sic)," Mr Gandhi said on Twitter.
Leader of Opposition in Karnataka Siddaramaiah also blamed the Karnataka BJP for his death.
Karnataka Congress President DK Shivakumar alleged that it was a "murder, not suicide". "If the BJP has any shame, they will immediately arrest the minister," he said, demanding "an immediate time-bound judicial inquiry into the alleged 'suicide' of Santosh Patil".
Chief Minister Basavaraj Bommai said the police will conduct a thorough and transparent investigation and ruled out any resignation.
"One thing I want to make it clear that this case will be thoroughly investigated. There will not be any interference or direction from our side. Police will independently investigate the case and truth will come out," Mr Bommai said, addressing a news conference.