Sonu, 32, had gone to the Rao Tula Ram (RTR) Hospital in Jafarapur on Sunday with his wife, where he had some quarrel with the hospital staff, a family member claimed.
"He was then thrashed by staff of the hospital and died of injuries later," the family member alleged.
Police said that it has received a complaint from the family, but not yet registered a case.
"We will take a call after the post-mortem report is out," a police officer said.
Medical Superintendent, RTR Hospital, Sangeeta Basu, denied the allegation, saying, "We have checked the CCTV footage, and there was no episode of any kind of assault, as alleged by the family."
"Sonu had first come to our hospital on February 11, when her wife had been brought by a police personnel, after she had consumed some unknown poison. In the evening, he again came to the hospital in drunk and started shouting," Basu claimed.
"We treated her and she was discharged. At 2 am, the wife then brought Sonu to the RTR Hospital, saying he was having pain in the stomach," Basu said.
The medical superintendent said, at around 12 noon on February 12, after examining him, "we referred him to the DDU Hospital, and he was sent in a conscious state, in an ambulance".
"We only heard of his death through the media reports," she said.