A 54-year-old tourist from Calcutta died in his hotel room at Lachung in North Sikkim on Friday from natural causes according to preliminary investigation, though the police have filed a case of unnatural death.

Biswajit Chakraborty of Jadavpur had reached Lachung, located at an altitude of 9,600 feet, along with family and friends on Thursday.

On Christmas, he complained of breathlessness and decided to stay behind in his hotel room with his wife while his son and friends went out sight-seeing.

Police sources, quoting his wife, said Chakraborty, a diabetic, could not cope with the high altitude of Lachung. “Since he said he was having difficulty in breathing, his wife decided to stay back in the hotel to take care of him. Unfortunately, he passed away before medical help could reach him,” said a source.

Chakraborty’s body was sent to the STNM Hospital in Gangtok for post-mortem on Saturday and later handed over to his family.

“We have registered a case of unnatural death though preliminary investigation suggests he died of natural causes. The actual cause of his death will be known once we get the autopsy report,” said the source.