ST. LOUIS, Mo -- A gunman opened fire at a St. Louis business this afternoon killing three people, before turning the gun on himself.
Investigators say the shooter worked at "Cherokee Place Business incubator" and got into an argument with three co-workers.
A witness inside the building called 911 when shots were fired.
Police say two women and two men, one of whom is the shooter, were shot to death.
A semi-automatic handgun was found at the scene.