The juvenile, who will turn major on July 9, was apprehended by police for attacking one Vijay, who is a bad character in Ambedkar Nagar Police Station area in south-east Delhi.
Vijay was fired at by the juvenile and one Ravi Gangwal on June 26 when he and his brother were at a shop in the area, police said.
"During course of investigation it came to notice that the injured Vijay is a notorious criminal and BC of PS Ambedkar Nagar. The injured reportedly had personal enmity with one Ravi Gangwal who is also a criminal and both had issues," a senior police official said.
Acting on a secret information, the juvenile was apprehended.
"He disclosed that he will be major on July 9 and hence he wanted to take revenge before that," he said.