1: NBA probes incident involving Jokic's brother and fan at Lakers game.

2: Video shows altercation between fan and Jokic's brother.

3: Witnesses describe tense moment at Lakers game.

4: Fan reportedly heckled Jokic's brother before altercation.

5: NBA promises thorough investigation into incident.

6: Jokic's brother defends actions, cites fan's behavior.

7: Lakers security intervenes in altercation at game.

8: Social media reacts to video of fan confrontation.

9: Incident raises questions about fan behavior at NBA games.