Indian police said Wednesday they are investigating the death of star Bollywood singer Krishnakumar Kunnath, popularly known as KK, who died at age 53 after a concert.
The singer died shortly after performing at a college festival in Kolkata on Tuesday evening, prompting a wave of tributes.
He was rushed to hospital from his hotel at around 10:30 pm, where doctors pronounced him dead.
Aroop Biswas, a government minister in the eastern state of West Bengal, said KK had died of a "suspected cardiac arrest".
But police said they are probing whether he died an "unnatural death", with media reports saying there were injuries to his face and head.
An autopsy was to be performed later in the day.
"We are also talking to the hotel authorities and scrutinising CCTV footage to understand what had happened before he was taken to the hospital," said police official Sanjoy Mukherjee.
Born in Delhi into a south Indian family, the versatile singer began his career with advertising jingles and recorded songs in Hindi, Tamil, Telugu, Kannada, Malayalam, Marathi and Bengali.
Like other playback singers in India who become stars in their own right, his songs were featured in films in which actors lip-synched along to his vocals.
His hits from the 2000s included "Aankhon Me Teri" from the movie "Om Shanti Om" and "Khuda Jaane" from "Bachna Ae Haseeno".
Prime Minister Narendra Modi led the tributes to the singer.
"His songs reflected a wide range of emotions (and) struck a chord with people of all age groups," Modi said on Twitter.
"We will always remember him through his songs. Condolences to his family and fans."
"I cannot believe that such a talented artist left us this way. He had two back-to-back programmes in Kolkata," composer Anupam Roy told AFP.
Fans paid tribute on an Instagram post put up by his management with photos showing KK singing in front of a roaring crowd.
The post was accompanied by the caption "Pulsating gig tonight at Nazrul Mancha ... Love you all."
"Rest in peace legend, you will be always in our heart," wrote one user.
"You're gone too soon!!!!!!" commented another.
One of the Hindi songs he sang at his last concert was "Pal", which has the lyrics "whether we live or not, we will remember this moment".
The Indian film industry has lost a string of luminaries in recent years, including superstar singer Lata Mangeshkar at 92 in February and veteran actor Dilip Kumar in 2021 at 98.
The year before, India lost much-loved singer S.P. Balasubrahmanyam as well as actors Irrfan Khan, Rishi Kapoor and Sushant Singh Rajput.
On Sunday, Sidhu Moose Wala, a rapper popular at home and among the Indian diaspora in Britain and Canada, was shot dead in the northern state of Punjab. Police believe the killing was related to organised crime.