CHICAGO (NBC 5) -- A Chicago police officer, a doctor and a pharmaceutical assistant have died after being shot Monday afternoon by a gunman at Mercy Hospital and Medical Center on Chicago's South Side, officials said. The gunman also was killed, police said, though it's not clear if it was self-inflicted or by police gunfire.
"It's with profound sadness that we share the death of PO Samuel Jimenez from tonight's senseless active shooter incident," police spokesman Anthony Guglielmi tweeted. "Please pray for his family, his fellow officers & the entire #ChicagoPolice Department."
Jimenez, from the 2nd District, joined the force in February 2017 and had just finished his probationary period as an officer, police Supt. Eddie Johnson said at a Monday night press conference. He and his partner were assigned to another location when they responded to officers needing assistance.
"Tonight, Officer Samuel Jimenez was shot and fatally wounded in a despicable act of violence," Johnson said in an email to police. "We are all deeply saddened by this tragic event and asked that everyone keep his family and co-workers in their thoughts and prayers."
"This tears at the soul of our city," Mayor Rahm Emanuel said. "It is the face and the consequence of evil."
Johnson said the incident started in the hospital parking lot at about 3:28 p.m., during a verbal altercation between the shooter and the doctor, who he was "in a domestic relationship with."
A friend tried to intervene in the argument, Johnson said, and the shooter lifted his shirt and displayed a handgun. The friend fled into the hospital, and the shooter shot the doctor, Johnson said.
As police arrived at the scene, the shooter fired at officers before they exited their cars, Johnson said. The man then ran into the hospital, and gunfire was exchanged between the suspect and police.
During the exchange, a pharmaceutical assistant exiting an elevator was fatally shot, Johnson said. Jimenez also was shot in the exchange and taken in critical condition to the University of Chicago Hospital. He later died from his wounds.
James Gray, a witness, told reporters that he saw at least one one woman shot near the hospital.
He said he saw a man and a woman talking to one another when the man pulled out a gun and shot the woman.
"Once he entered he just started shooting at random," Gray said. "It looked like he was turning and pointing at people at random."
A Twitter user posted video of what appeared to be Chicago police officers searching the interior of the hospital.
"The shooting at Mercy Hospital is over," the hospital said on Facebook. "Chicago Police Department have secured the hospital and patients are safe."
The Bureau of Alcohol, Tobacco, Firearms and Explosive's Chicago Field Division was responding to the scene to assist other local authorities.
Police asked that people avoid the area.