1: NBA investigates fan-punching incident involving Nikola Jokic's brother.

2: The league takes swift action against fan misconduct.

3: Security measures tighten at NBA games.

4: Players' safety becomes top priority for NBA.

5: Jokic's family expresses concern over fan behavior.

6: Fan banned from future NBA games.

7: Zero tolerance for violence in sports.

8: NBA community stands against fan aggression.

9: Jokic brothers call for respect and civility.