They said two men were arguing about pitchers with the Toronto Blue Jays when a third man allegedly sucker punched Brian Ludwig.
Police found the 41-year-old suffering from severe head injuries in the Swigs Pub parking lot when they arrived on scene.
Ludwig was rushed to hospital, but died a short time later.
"The witnesses were very co-operative with this investigation and as a result of our interviews we were able to identify a suspect early in the investigation," said Staff Sgt. Doug Andrus.
An autopsy conducted Monday determined the cause of death was blunt force trauma.
Scott Hooser, 27, has been charged with manslaughter and made his first court appearance Tuesday morning.
He'll be back in court on Friday, the same day a memorial service has been planned for Ludwig.