A spokesperson says the NBA is “looking into” an apparent incident involving Denver Nuggets superstar Nikola Jokić’s brother, Strahinja Jokić, which happened after the Nuggets won their home game against the Los Angeles Lakers on Monday night.

A video posted on social media overnight Tuesday appears to show Strahinja Jokić wearing his brother’s No. 15 jersey, stepping over a row of seats to confront another fan and then punching him in the head.

The Denver Police Department (DPD) says it’s aware of the video and is looking into what happened, noting that the incident at Ball Arena wasn’t reported to police.

DPD says “no one has come forward as a victim” but the department “is actively working to identify the person in the video who was struck and encourages anyone who was involved or witnessed this firsthand to contact the Denver Police Department.”

CNN has reached out to the Nuggets, Lakers and security at Ball Arena for comment.

It is not clear what transpired before the incident.

Nikola Jokić, who is in the running to win a third MVP award after another dominating season, scored 27 points, grabbed 20 rebounds, and dished 10 assists against the Lakers on Monday in Game 2 of their first round playoff series.

The Nuggets took a 2-0 series lead after Denver’s Jamal Murray hit a game-winning, buzzer-beater to cap a dramatic 101-99 comeback win.