Police then shot and killed the gunman, who investigators believe had a “personal relationship” with an employee at the Duck Creek restaurant inside the Radisson Hotel & Conference Center attached to the casino, Pawlak said.
The person the gunman was targeting wasn’t at the casino at the time, so the gunman instead shot the intended target’s “co-workers or friends,” Pawlak said.
Authorities said there is no longer a threat to the community.
Two witnesses described the scene as chaos, hearing gunshots and seeing people “running for their dear lives.”
“Pretty thankful we could get out of there, and all of us are safe,” Luehring said.
Adam Olig, also of Mayville, told the station the scene was chaotic.
“Seen people that were a lot closer. There were people running all over the place, running for their dear lives,” Olig said.
“It was chaos all over. People scattering in all directions. It was just crazy. Just crazy,” Luehring added.
The casino urged in a tweet for people to avoid the area as the investigation continues.
CNN has reached out to the area fire department, police, sheriff’s office and nearby hospitals for more information.
CNN’s Jessica Flynn and Andy Rose contributed to this report.