CHICAGO (WLS) -- Chicago police said three people were shot, including a child, and one of them was killed at a Starbucks in the city's Uptown neighborhood Thursday night.Cmdr. Marc Buslik of the 19th District said the shooting occurred at the Starbucks in the 4700-block of North Broadway Street at about 8:10 p.m.Buslik said the victim who was killed in the shooting had an interaction, possibly a drug deal, with the suspect on the sidewalk at North Broadway and West Wilson Avenue. The victim then ran to the Starbucks, chased by the suspect.The suspect opened fire inside the Starbucks, striking three people including a 12-year-old boy."We were outside and heard two shots, then a pause, and I grabbed my wife and kind of pushed her down and said 'Shots!' And then there were three more almost within a few seconds," said Mike Swaiko, who was across the street at the time of the shooting. "The manager of the bar, the bartender, opened the door and said 'Everybody get the heck inside.' And we got inside.""So by the time we got in there they had already told everybody to get cover and then they locked the door," said Marie Swaiko.Police said the man who had been involved in the possible drug deal died at the scene. Another adult male was shot and is at Illinois Masonic Hospital in serious but stable condition. The 12-year-old boy was shot in the groin and is at Lurie Children's Hospital in serious but stable condition, police said.Buslik said he believes the victim who was killed was the only intended victim, and that the three who were shot did know each other. It was not clear if the 12-year-old was related to either of the two other victims.Buslik said there is not considered to be a wider danger to the public. He said the suspect fled southbound on Broadway. He is described as a black male wearing dark clothing, who may also have been wearing a mask.A spokesperson for Starbucks said they are dismayed to hear about the gun violence and are working with law enforcement to obtain more information.