Mercy Hospital & Medical Center underwent a fatal shooting incident where 3 victims were killed: a young police officer, a pharmacist, and a doctor, in addition to the gunman himself.
the attack started with an argument in the Mercy Hospital parking lot between the gunman, 32-year-old Juan Lopez, and Dr O'Neal at about 15:00 on Monday.
it was revealed that the shooter used to be Dr O'Neal fiance and that they were intending to marry on 27 October.
The gunman shot Dr O'Neal, 38, several times in the chest before standing over her and firing three more times The suspect then entered the hospital, shooting at random and killing newly graduated pharmacist Dayna Less, who was getting out of a lift at the time. In an exchange of fire with the gunman, policeman Samuel Jimenez was killed; a second officer avoided injury after a bullet fired in his direction became lodged in his gun in his holster.
Hospital patients scrambled to find cover under desks, police and Swat teams moved through the hospital in search of the gunman, and officers locked down hospital wings, including the nursery.
The suspect died, though it was not immediately clear if he shot himself or was struck by a police bullet.
a Memorial bunting has been installed to honour the young policeman at the Chicago police headquarters.