Kolkata Police has registered a case of unnatural death over the demise of renowned Bollywood singer Krishnakumar Kunnath, popularly known as KK, and started an investigation, even as opposition BJP blamed the West Bengal government for lapses, drawing a sharp retort from the ruling TMC which asked the saffron party not to politicise death.

Post-mortem examination of the singer's mortal remains was conducted and the report is awaited, police said.

"Police have spoken with the manager and other staffers of the hotel where KK had put up. A case of unnatural death has been registered with New Market Police Station, under whose jurisdiction the hotel falls where the singer felt unwell before being taken to a hospital," an officer told PTI.

"We are scrutinising CCTV footage to understand what had happened before he was taken to the hospital," the police officer said, adding that two persons have been questioned in connection with the case.

An initial probe has revealed that the 53-year-old singer, who was on a two-day tour to Kolkata to perform at two college programmes, was "almost mobbed" by fan followers at the hotel where he had returned to after performing at Nazrul Mancha auditorium in the southern part of the city, he said.

"The singer had allowed a couple of fan followers to take snaps with him, but then he refused to carry on with the selfie session. He left the lobby and then went upstairs where he had reportedly stumbled and fallen on the floor. People who were with him informed the hotel authorities," the officer said.

KK was then rushed to a private hospital in the southern part of the city where he was declared "brought dead" by doctors, he said, adding that probably because of the fall, the singer had two injuries -- one on the left side of his forehead and another on his lips.

Cardiac arrest suspected

"He was brought to the hospital around 10 pm. It's unfortunate that we could not treat him," a senior official of the hospital said. Doctors at the hospital said they suspected "cardiac arrest" to be the cause of the death. "The autopsy report will throw light on the exact cause of death. We are waiting for it," the police officer said.

Gun salute

The West Bengal government paid its last respects to KK with a gun salute to his mortal remains.Chief Minister Mamata Banerjee, who supervised the proceedings, paid floral tributes to the late singer, whose body was kept at Rabindra Sadan for some time. Banerjee was seen consoling KK's wife and other family members who were present at the venue.

The singer's body was brought to Rabindra Sadan after a post-mortem examination was conducted at state-run SSKM Hospital earlier in the day, an official said. His mortal remains were taken to Netaji Subhas Chandra Bose International Airport and handed over to his family, who will fly to Mumbai with the body, he said.

Banerjee cut short her programme in Bankura district and reached Kolkata.

"The sudden and untimely demise of the Bollywood playback singer KK shocks and saddens us. My colleagues have been working from last night to ensure that all requisite support is given for necessary formalities, his rites and to his family now. My deep condolences," she tweeted.

"KK was a youth icon. We have lost a great singer," she said.The singer had performed at Nazrul Mancha Tuesday evening and also on Monday. He was scheduled to return to New Delhi on Wednesday.

Mismanagement, cris BJP

The incident triggered a political blame game with the BJP demanding an impartial probe, while the TMC asking it not to politicise death.

"There should be an impartial investigation into the incident as there was a complete lapse on the part of the administration to ensure proper security arrangements.

"Around 7,000 people were reportedly present at the venue of the programme where the seating capacity was around 3,000 people. He was mobbed there, which means security arrangements were not in place for a VIP," BJP state spokesperson Samik Bhattacharya said.

Echoing him, BJP national secretary Anupam Hazra said strict action should be taken against the organisers.

How many were allowed entry?

"What was the capacity of the hall and how many people were allowed entry? Was the air-conditioning enough for such a gathering? What was the oxygen level at the auditorium? These things need to be looked into," he tweeted in Bengali.

West Bengal Congress chief Adhir Ranjan Chowdhury also demanded an inquiry by a "competent authority".

"All said and done I do demand a thorough inquiry behind the sad demise of singer #KK by a competent authority. The prevailing ambience of the Najrul Mancha during his performance reveals many unsavoury questions including critical mismanagement of the said platform which might have triggered his death," he tweeted.

Stop vulture politics: TMC

Reacting sharply to BJP's comments, TMC state general secretary Kunal Ghosh said the saffron party should stop its "vulture politics" and should not politicise an unfortunate incident.

"His death is really unfortunate, and all of us are really sad about it. But what the BJP is doing is not at all expected. The saffron camp should stop its vulture brand of politics. They should stop politicising death. We won't be astonished if BJP starts claiming that KK was their party leader," he said.

Ghosh said the administration is taking all measures and an investigation is underway.

'AC was working'

Senior state minister and Kolkata Mayor Firhad Hakim said air-conditioning was working but there was an overwhelming crowd.

"KK was a very popular singer and had a huge fan following among the young generation. I have heard that the capacity was around 2,800 but around 7,000 people had tried to enter the hall to have a glimpse of him and listen to his song.

"You can't ask the police to baton charge a crowd as they wanted to listen to his song. The air-conditioning was completely in order. I would request everyone not to politicise death," he said.

Initial hits such as 'Pyaar Ke Pal' and 'Yaaron' made KK popular among the youths of the country. As a playback singer, he has recorded Bollywood numbers such as 'Ankhon Mein Teri' (Om Shanti Om), 'Zara Sa' (Jannat), 'Khuda Jaane' (Bachna Ae Hasino) and 'Tadap Tadap' (Hum Dil De Chuke Sanam).

A versatile singer, KK has also recorded songs in Tamil, Telugu, Kannada, Malayalam, Marathi and Bengali, among other languages.