Chicago police released an October 2018 booking photo of Nightengale that was taken after he was charged with multiple driving-related offenses, including driving on a suspended license.
"While we are still learning more about the offender, his motive, and the totality of [Saturday's] tragic events, one thing is clear: If not for the courageous actions of Evanston and Chicago police, many more innocent lives would have been lost", said Hagerty.
Among the fatal victims killed in the shooting spree in Chicago and Evanston include a security guard at an apartment complex and a student at the University of Chicago.
Investigators are trying to determine a motive for the attacks, which began Saturday afternoon with the killing of a 30-year-old University of Chicago student who was shot in the head while sitting in his auto in a parking garage in the Hyde Park neighbourhood, Chicago police Superintendent David Brown told reporters. The woman was shot in the chest and was pronounced dead at a hospital a short time later, according to police.
Chicago police identified the suspect as 32-year-old Jason Nightengale.
At approximately 5:40 p.m. the scene shifted to Evanston, where Nightengale allegedly entered an IHOP, took a female hostage, then shot her, fatally wounding her.
Nightengale's next believed move was to return to the area of the convenience store shooting, where police were investigating the incident.
The rampage started around 1:50 p.m. local time.
The first victim of the crime was a University of Chicago postgraduate student.
The University was notified that a student had been discovered in a vehicle with a gunshot wound, officials said in a statement to the university's community.
"This is deeply painful news for our community and South Side neighborhood, and we will provide support to those affected". The suspect asked to use a phone before opening fire.
At around 2:45 p.m, Nightingale went into a building in the 5500 block of South East End Avenue in Hyde Park, where a relative of his reportedly used to live.
Four of the victims were in critical condition. Nightengale had apparently walked into the pharmacy, announced that he was robbing it and fired off shots that didn't hit anyone, authorities said.
An 81-year-old woman inside the store was shot in the back and the neck and was transported to the hospital in critical condition, according to police.
Nightengale is then alleged to have shot a 15-year-old girl while she was sitting in the backseat of a vehicle in the nearby Fernwood neighborhood at around 5 p.m.
The woman was taken to the hospital, where she is now in critical condition.