Who is the Chicago Mercy Hospital Shooter? Juan Lopez, 32, Targeted Fiancee with 9 MM Handgun, Police Say

Update: After Police officers initially kept the man's identity anonynmous, he was identified as Juan Lopez, according to CBS Chicago.

Juan Lopez, 32, was identified by authorities as the lone suspect in the Mercy Hospital shooting that occurred on Monday afternoon, according to Chicago Police.

Four people, including Lopez, died in the shooting, according to Chicago police spokesman Anthony Guglielmi. The victims include a police officer and at least three hospital employees.

Gugliemi referred to the shooter as a "cowardly" and initially chose to keep him nameless as of Monday evening. A source told CBS Chicago that Lopez was fatally shot by a SWAT team officer, although it was unclear how he was killed during the police conference on Monday.

One of the victims was reportedly Lopez's former fianceé, Dr. Tamara E. O'Neal, who was believed to be the primary target, according to ABC 7 in Chicago.

Lopez fatally shot O'Neal, 38, in the hospital's parking lot with a 9mm handgun, which was witnessed by an acquaintance of the former couple, prior to entering the hosptial on a shooting rampage, Police Superintendent Eddie Johnson announced during a press conference on Monday night.

Gugliemi also confirmed the death of police officer Samuel Jimenez via Twitter on Monday night.

The shooting took place around 3:20 p.m. CST in the city's South Side area and officers searched the hospital.

Gugliemi confirmed the incident via Twitter on Monday evening, saying, "Reports of multiple victims from incident at 26th and Michigan. Please avoid area."

Chicago PD spokeswoman Christine Calace confirmed to the Associated Press that initial reports indicated that shots were fired inside and outside the hosptial building.

Gugliemi also tweeted that police were "doing a methodical search of Mercy hospital. At least one possible offender is shot."

Steven White, a patient who was waiting to be discharged at the time of the incident, revealed that the shooting began outside the hospital near the emergency room entrance.

"It was, 'Pow, pow, pow,''' said White, who was being treated for dehydration.

White said he could see people inside the hospital lying on the ground through the window at the time of the incident. The gunman reportedly fired two more shots at one person lying on the ground, according to White.

"You see stuff like this on TV, but to see someone so cold-hearted," White said. "It was like he had no remorse."

The gunman reportedly ran into the building and was chased by a police officer. White told the AP that he believes he heard the gunman fire another half dozen shots as bystanders took cover for protection.

James Gray told ABC 7 in Chicago that he witnessed multiple people shot: "It looked like he was turning and shooting people at random."

Mayor Rahm Emanuel reportedly met with Chicago Police Superintendent Eddie Johnson at the city's public safety headquarters where authorities monitored the events, the mayor's spokesman, Adam Collins, confirmed on Monday.

Chicago recorded 488 murders for 2018 as of Nov. 11, the most of any United States city and had also recorded 650 in 2017 and 762 in 2016.

Mercy Hospital and Medical Center houses 292 patients and is a medical and surgical Catholic teaching hospital that opened its doors in 1852.

Monday's shooting takes place just a few weeks removed from two other gun-related murders, one at a bar in Thousand Oaks, California, and another at a synagogue in Pittsburgh.

Correction, 11/19: This story originally stated that police left the gunman's name anonymous. His identity was announced as "Juan Lopez" after the initial article was published during a police press conference.