The accused has been identified as Aamir alias Hamza (22), a resident of New Seelampur. He works as a casual labour and had been involved previously in another case, they said.
The incident took place on 6 August while the accused was attending a function organised by a man named Qutubddin to celebrate the birth of his child, police said.
After receiving information about the firing incident, the police rushed to the spot and found that the injured children had already been shifted to the JPC hospital by their parents and locals, a senior police officer said.
The complainant Wasim told the police that with a pistol in his hand, Aamir had started scolding the children for playing on the street and asked them to leave, he said.
When Wasim noticed this, he had a heated argument with Aamir following which the accused fired a bullet, police said.
"The bullet rebounded and the three children, aged between 7-13 years, sustained injuries. After firing the bullet, Aamir fled the spot," the officer said.
All Three Children Out of Danger
All the injured children are out of danger now, police said.
A case was registered under sections of attempt to murder (307) of the Indian Penal Code and other sections of Arms Act at Seelampur police station, he said.
"During investigation, a police team scanned and analyzed footage from CCTV cameras in the vicinity to ascertain the escape route of the culprit.
"Technical surveillance as well human sources were also deployed. Within hours, police team zeroed-in on his location and Aamir was apprehended," said Sanjay Sain Singh, Deputy Commissioner of Police (Northeast).
A sophisticated semi-automatic pistol, loaded with two live cartridges, was recovered from his possession, he said.