The Kolkata Police on Wednesday registered a case of unnatural death in connection with the demise of singer Krishnakumar Kunnath, popularly known as KK, ANI reported.

KK died on Tuesday night shortly after performing at a concert at the city’s Nazrul Mancha auditorium. He collapsed at the hotel where he was staying after the performance. Doctors at the Calcutta Medical Research Institute said that the singer had died by the time he was brought to the hospital.

While doctors said that they suspected cardiac arrest to be the reason for his death, the police said that a post-mortem examination will be conducted on Wednesday to identify the exact cause.

The singer was on a two-day visit to Kolkata to perform at two college events. Initial investigation showed he was “almost mobbed” by fans at the hotel where he returned after the performance, a police official told PTI.

“The singer had allowed a couple of fan followers to take photos with him, but then he refused to carry on with the selfie session,” he said. “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.”

KK reportedly sustained two injuries – one on the left side of his forehead and another on his lips – possibly due to the fall.

On Wednesday, the police questioned two persons in connection with the singer’s death, PTI reported. “We are talking to the hotel authorities and scrutinising CCTV footage to understand what had happened before he was taken to the hospital,” the police official said.

M Hussain, a staff member at the auditorium, said that the venue was packed beyond its capacity, ANI reported. “...Crowd was jumping from the boundary and some broke the gates,” he said.

Videos shared on social media showed that KK was visibly in discomfort during the concert. In one of the videos, he was seen wiping sweat and apparently gesturing that the air conditioning at the venue was not working. A person was heard saying it was extremely hot there.

Another video showed KK saying “God bless you all” to the crowd before leaving the stage in a hurry. He was visibly distressed as he was taken away from the venue.

A third video showed the exhausted singer being taken back to his hotel after the concert.

Meanwhile, West Bengal Chief Minister Mamata Banerjee said that the state police will give a gun salute to the singer, according to PTI. Banerjee added that she had cut short a tour and will try to reach the Kolkata airport to pay her last respects to him.