Fans and bystanders celebrating the Kansas City Chiefs’ Super Bowl win Wednesday chased and tackled a person who police say could be one of three people who were detained, according to video and the police chief.

Officials have not confirmed that the person in the video is in police custody and being investigated after gunfire killed one person and injured more than 20 other people Wednesday afternoon in downtown Kansas City, Missouri.

“We do have three persons detained and under investigation for today’s incident,” Police Chief Stacey Graves said at a news conference. “We are working to determine if one of the three are the one that was in that video, where fans assisted police.”

Video shows police taking someone into custody, and a bystander can be heard saying, “When we tackled him, the gun come out.”

Police have not identified anyone who has been detained, and they have not said anyone has been charged. Police used the word “detained,” not “arrested.”

The shooting happened outside Union Station in downtown Kansas City around 2 p.m. local time (3 p.m. ET) at the conclusion of the victory parade and rally celebrating the Chiefs’ overtime win over the San Francisco 49ers in the Super Bowl on Sunday.

About 1 million people had been expected to attend the celebration, and bystanders reported police officers jumping barricades and running to the scene, while other fans fled and yelled about an active shooter.

Officials say they do not believe the motive was terrorism. Graves, the police chief, said “bad actors” caused the chaos and bloodshed, even amid a police presence that included more than 800 law enforcement officers at the event.

Mayor Quinton Lucas said he was among the people forced to run for safety.

“This is absolutely a tragedy, the likes of which we would have never expected in Kansas City and the likes of which we will remember for some time,” he said.

Lucas also said he and his wife “became part of the statistic of too many Americans — those who have experienced or been part of or connected to a mass shooting.”

This article was originally published on NBCNews.com