A 100 block S. Van Dorn St. apartment complex pool patron suffered minor injuries after another man attacked him without warning on June 8. 

The victim was speaking with a lifeguard when the other man, described as a black and with a thin build, hit him at about 9 p.m., said Ashley Hildebrandt, department spokeswoman. 

Authorities dont know why the man struck. They have not yet made an arrest.