4 dead, including Chicago officer, after Mercy Hospital shooting

CHICAGO — Four people were killed, including a Chicago police officer and a gunman, after an active shooter incident at a South Side hospital.

Chicago police responded to the scene at Mercy Hospital and Medical Center at 2525 S. Michigan Avenue for reports of shots fired just before 3:30 p.m. Monday. The incident may have started with gunfire in the parking lot before moving into the hospital.

The officer was initially in critical condition, according to CPD spokesperson Anthony Guglielmi. The officer, identified as Samuel Jimenez, was 28 years old and had just completed his probationary period. Jimenez leaves behind a wife and three kids.

A doctor and a pharmaceutical assistant were also killed in the shooting . Sources told WGN a female doctor was believed to be the intended target by a man who was her ex-fiance who then went inside and continued shooting. At least 15 medic units responded to Mercy hospital, Chicago Fire Department Public Information Officer Larry Merritt said.

Eyewitness: “she asked us not to leave her alone”

An eyewitness sitting in a van full of nursing home patients watched in horror as the incident unfolded.

The witness, who asked to not be identified, said they were in the parking lot of Mercy Hospital when a woman ran from the hospital and asked for help.

“She got on the phone and she was trying to call the police,” the witness said. “She asked us not to leave her alone because he is going to kill her.”

The witness said a man demanded the woman give him a ring, and the woman replied that she didn’t have it. She started going back towards the hospital to get security, the witness said, when the man re-emerged with a gun.

“The guy comes really quickly from behind the van and just pulls out a gun and shoots her six times before she even hits the ground,” the witness said.

The van drove off and headed towards the exit just as police were entering the parking lot.

“He started firing in our direction and at the cops,” the witness said.

Another witness, who said they worked at the 2600 South Michigan Avenue building, said she heard five shots. She went to a window and saw someone running into the hospital. She said she saw officers shooting back and forth.

“The police came from everywhere. I mean within seconds they were just surrounding the hospital, firefighters and ambulances, everything, they were just surrounding the hospital,” she said. “The person was there right, shooting, they were behind the cars, protecting themselves, and at that point I just said you know what, I don’t know where this person is, I don’t know if they’ve come out or if they’re still in there, so we got away from the windows.”

Maria Teo, a nurse at the hospital who was registering a patient when the incident started, said just one month ago, she underwent active shooter training. She said no matter how much training you get, you will never be prepared for the real thing.

"I was texting, I called my mom, whispered to her the situation. She didn't wanna believe it," Teo said. "I texted my family and all I thought about was my kids. My daughter asked me if I was okay, and all I said was 'I love you,' and she was like, 'I know something is wrong.' I'm like, 'I'm OK, I'll text you, I just can't talk to you right now, but I'll keep texting you.'"

WATCH: Chicago police give update after fatal hospital shooting