Russian authorities have launched an inquiry after a shocking CCTV video of a doctor punching a patient and killing him instantly in a hospital in the city of Belgorod emerged. The footage has now gone viral on social media sites and has since aired on state television.

In a statement released on 9 January, a Belgorod investigative committee said the incident had taken place on the 29 December 2015, where the doctor confronted a bare-chested man who had potentially man-handled a female nurse. The doctor said: "Why did you touch the nurse?" before pushing him out of the doorway. When the man returned, the doctor delivered the fatal blow to the face.

It has not been explained why the investigation of the crime has been delayed, but the doctor is now expected to be charged with death through negligence that carries a two-year jail sentence.

During the incident at the hospital estimated to be 670km (440 miles) south of Moscow, the doctor is also seen scuffling with another man accompanying the patient and it is not noticed until minutes later that the first man is lying motionless on the floor after which other doctors try in vain to revive him.

They then drag away the man's body away after which an orderly mops up blood stains. The delay of the investigation of the footage has led to accusations of a cover-up. Russian media named the doctor as a surgeon Ilya Zelendinov and the patient as 56-year-old Yevgeny Bakhtin.

The Russian medical industry has been subject to a veil of secrecy. In September 2015, a Russian plastic surgeon was shot dead by a disgruntled patient, who was unhappy with how his nose job turned out. Dr Alexander Remizov was also shot dead by former patient Yury Lebedev, 34, after the assailant entered his office at the Russian Railways hospital in Saint Petersburg armed with a rifle.