The incident took place around 11.15 pm on Sunday at Dhaka village in north Delhi's Mukherjee Nagar.
Tarun Chauhan, a class 7th student studying in a government school, received a bullet in his chest when the accused opened celebratory fire at the marriage ceremony.
"He was rushed to Sushruta Trauma Centre in the Civil Lines area where doctors declared him brought dead," said a senior police officer.
The accused, identified as Jai Baba, 35, is deputed as a constable in the Delhi Police crime branch. He has been arrested and a case registered against him.
Manmeet, a cousin of the bride, had invited Baba and Sanjay, a constable deputed in west Delhi's Subhash Place police station, to the ceremony.
The accused had consumed alcohol during the ceremony along with Sanjay and three-four other friends.
"After consuming alcohol, they were on the dance floor where Baba took out his service revolver and fired two shots in the air. He then fired a straight shot. The bullet pierced the victim's chest who was also dancing on the stage," said the official.
The enraged relatives of the victim beat up the accused and handed him over to police, said the official.
For NDTV Updates, follow us on Twitter or join us on Facebook
