Chicago hospital shooting: Police officer shot at saved after bullet got embedded in his gun

A police officer who was fired upon during a shooting at a Chicago hospital was saved after a bullet hit his gun.

The officer had confronted the gunman, who killed three people including a fellow cop, at Mercy Hospital during the horrific incident on Monday afternoon.

Images show his damaged holster and a bullet lodged into the side of the gun. The officer was remarkably uninjured.

His colleague, 28-year-old Samuel Jimenez, died in the shooting which started with an argument in the car park of the hospital. The former partner of an emergency room doctor is said to have pulled a gun from his waistband and opened fire.

Doctor Tamara O'Neal, 38, was shot dead in the car park, while bystander Dayna Less, 25, a first year pharmacy resident, died when she came out of a lift in the building.

A friend of Ms O'Neal had tried to intervene in the argument when "the offender lifted up his shirt and displayed a handgun," Chicago Police Department Superintendent Eddie Johnson said.

The friend then ran into the hospital to get help, and gunfire began seconds later.

After Ms O'Neal was shot she fell to the ground. The gunman "stood over her and shot her three more times," a witness named James Gray told reporters.

Officers then arrived and the suspect fired at their squad car and ran inside the hospital. The police gave chase.

Inside the hospital, the gunman exchanged fire with officers and "shot a poor woman who just came off the elevator", Supt Johnson said, referring to pharmaceutical assistant Ms Less.

"We just don't know how much damage he was prepared to do," he said, adding that Ms Less "had nothing to do with nothing."

Mr Jimenez was also shot inside the hospital. He was later pronounced dead.

The gunman, who has been named locally as Juan Lopez, was also killed in the incident, although it is not clear whether this was self-inflicted.