A 32-year-old man was shot dead at a Delhi government hospital on Sunday, said the police.
The incident was reported from the third floor of the Guru Teg Bahadur Hospital in the city at 4 pm.
Riyazuddin, who complained of a stomach ache, was admitted to the hospital on June 23.
"A patient, named Riyazuddin, has been shot dead in GTB hospital. He was a resident of Khajoori Khas. We are scanning the surveillance footage," said Vishnu Kumar Sharma, Additional Deputy Commissioner of Police, Shahdara.
The unnamed attacker, who is on the run, is an 18-year-old who fired 3-4 rounds, said police.
It is not clear what was the provocation behind the attack, the police added.
"A doctor was bandaging him (Riyazuddin) when the attacker burst on the scene. The attacker fired five shots and ran away. There was chaos and confusion," said Chancal, a cleaning staff member at the hospital, a witness to the attack.
Disturbing pictures from the scene showed the man in a pool of blood in his hospital bed with a pink blanket covering him waist down.
Delhi Health Minister Saurabh Bharadwaj said the government will review security at hospitals.
"Negligence will not be tolerated; whoever is guilty will not be spared. There will be a review of security of all hospitals," said the Delhi Minister.