The Chicago Cubs are investigating a fan who appeared to flash a white power sign in back of a black reporter during a live broadcast, team officials said.

Doug Glanville, a former outfielder for the Cubs now working as an analyst for NBC Sports Chicago, was covering Tuesday night’s game at Wrigley Field against the Miami Marlins when a fan seated behind him used his left hand to form an upside-down “OK” symbol — a hand gesture sometimes associated with white supremacy.

“We are currently investigating an incident that occurred during the Cubs’ May 7 broadcast on NBC Sports Chicago while reporter Doug Glanville was on the air,” Cubs president of business operations Crane Kenny said in a statement to The Post. “An individual seated behind Mr. Glanville used what appears to be an offensive hand gesture that is associated with racism.”

The fan, clad in a Cubs pullover, initially flashed a peace sign while seemingly trying to disrupt Glanville’s report. He then tried a different approach by forming the apparent racist hand gesture for several seconds before the camera abruptly cut away to a graphic, video shows.

“Such ignorant and repulsive behavior is not tolerated at Wrigley Field,” the team’s statement continued. “We are reviewing this incident thoroughly because no one should be subjected to this type of offensive behavior.”

The fan, if identified, could be banned from Wrigley Field for life. Cubs spokesman Julian Green said the team was working early Wednesday to identify him and exactly where he sat during the game.

“Any derogatory conduct should be reported immediately to our ballpark staff,” the statement continued. “Any individual behaving in this manner will not only be removed from the ballpark, but will be permanently banned from Wrigley Field.”

Several users on Twitter immediately spotted the gesture by the Cubs fan and called him out, saying he should lose his seat for using the “white power sign” at the ballpark. At least one fan watching the game asked people to help identify the “incredible hunk of s–t” who flashed that “white nationalist” finger gesture, prompting another user to zoom in on his face during the brief snippet of footage.

The Southern Poverty Law Center said the gesture has been used for years by several alt-right figures — including Richard Spencer and Milo Yiannopoulos — dating back to as early as 2015. It then became 4chan fodder in early 2017 when trolls tried to “trigger liberals” by making them believe the simple hand gesture was associated with racism, despite the fact the sign could be easily mistaken to mean that “everything is OK.”

“From its adoption first by white nationalists, and then by 4chan trolls intent on ‘triggering the libs,’ the well-known hand signal’s use points to deeper concerns,” the legal advocacy group wrote in September 2018. “The smirk gives away the proper answer: You’re being trolled.”