Chicago hospital shooting leaves four dead, including police officer and gunman

A gunman shot to death a doctor outside a Chicago hospital on Monday before bursting into the facility and killing a woman and a police officer during an exchange of gunfire and dying in the shooting, officials said.The shooter knew the doctor he shot outside Mercy Hospital, but once inside he fired randomly at people, Chicago Police Superintendent Eddie Johnson said at a news conference.The shooting sent doctors and patients streaming out of the facility, some with their hands up as heavily arm