FOREST PARK, Ill. (CBS) — A man was charged Tuesday afternoon in connection with the mass shooting that killed four people died on CTA Blue Line train in the western suburb of Forest Park the day before.

Rhanni Davis, 30, of Chicago, was charged with four counts of first-degree murder, said Forest Park police, who announced the charges Tuesday evening, as did Cook County District Attorney Kim Foxx and Chicago Transit Authority President Dorval Carter.

All four victims were passengers on a Blue Line train heading to the Forest Park terminus when they were shot just before 5:30 a.m.

Police said three victims were found dead at the scene. A fourth victim was taken to a local hospital where he died. Officers had identified two of the victims by Tuesday afternoon — Simeon Bihesi, a 28-year-old man, and Adrian Collins, a 60-year-old man.

Collins died from a gunshot wound to the abdomen, while Bihesi died from multiple gunshot wounds.

The Cook County Coroner’s Office said one of the two other victims was a 52-year-old man, whose identity remains undisclosed pending notification of next of kin, and the other victim was a 64-year-old woman, now identified as Margaret Miller.

CTA Security and Forest Park Police used surveillance footage to find the suspected shooter. The suspect was found on a CTA Pink Line train at the California Avenue stop in Little Village and taken into custody Monday morning.

The weapon was recovered. It was a 9mm Glock 43 with six rounds of ammunition, according to Forest Park Police Lt. Daniel Pater, who leads the unit.

Investigators said Davis matched six shell casings found in two cars at the Blue Line Forest Park stop.

Investigators say Davis began shooting near the Harlem station on the Oak Park-Forest Park Village line — one stop before the terminal. Davis was wearing a mask at the time, investigators said.

Police said the shooting appeared to be an isolated incident and that the suspect did not appear to know any of the victims, who appeared to be asleep during the train ride. Police also said it did not appear the shooter was trying to rob the victims and that the attack was completely random.

“We should have the freedom to ride the train, to do yard work, to meet up with friends on our porches,” Foxx said. “Public transit should be a safe space for everyone.”

Foxx noted that just two weeks ago, Chicago shined — hosting more than 50,000 people — at the Democratic National Convention.

“The incident that has occurred over the last 24 hours is a stark reminder of how far we still have to go,” Foxx said.

Foxx added, however, that she doesn’t yet have answers about the motive behind this “disgusting, heinous act” and fears we never will.

“It’s terrifying,” Foxx said. “We want answers.

Meanwhile, Carter said CTA employees immediately began assisting police once they learned of the horrific crime — helping with tasks such as reviewing security footage. He also focused on the CTA’s focus on safety.

“To our passengers, we want you to know that we hear you and understand your safety concerns. The men and women of the CTA are united in our commitment to ensuring that we are doing everything we can to protect our passengers as well as our employees,” Carter said.

Carter said he could not say whether the four people shot on the train were homeless.

“I can tell you that when it comes to homelessness, we have engaged and provided more resources to homeless individuals who use CTA than ever before in the history of our agency,” he said.

As part of this effort cooperation with social agencies whose representatives are in the system every night to provide homeless people with housing options other than sleeping on the CTA.

Carter added, however, that the CTA alone will not solve crises such as homelessness or addiction.

“Dealing with crime on the CTA is a very complex problem that requires multiple layers of security and policing,” Carter said.

Just last week, The CTA announced it is implementing a pilot program that will incorporate artificial intelligence gun detection technology into its system.Carter said the ZeroEyes artificial intelligence software was not a factor in this case.

The ZeroEyes software scans for firearms only on platforms, and Carter said a decision on expanding it to trains will be made once the pilot is complete.

The entire mass shooting was caught on camera.

Cameras on the trains captured everything that happened during the mass shooting. CBS News Chicago was told the footage was shocking and would be used as evidence.

“It’s unusual for there to be multiple homicides on a CTA train,” said CBS News Chicago legal analyst Irv Miller. “The CTA has more cameras — high-definition cameras — than any other place in the county, so someone basically had to say, ‘I’m going to do this and I don’t care if I get caught.’”

Davis has been arrested several times since 2014 — and was sentenced to two years of probation for misdemeanor battery that same year. He also pleaded guilty in 2020 to disorderly conduct.

If Davis is convicted of four counts of first-degree murder, the only sentence that applies in Illinois is life in prison without the possibility of parole. Miller explained that the mental state issue is really the only defense that applies in Davis’ case.

“There are defenses under the law, and one defense that comes to mind in a case like this is the insanity defense. If it’s raised, it doesn’t matter whether it’s on videotape or not. The question is, what’s the person’s mental state — was he able to appreciate the criminality of his behavior?” Miller said. “So when you shoot four people while they’re sleeping — and it’s on videotape — you don’t have many defenses available to you, quite frankly.”

A mass shooting occurred when CTA President Carter was already under fire — calls for his resignation having done headlines in mayIn light of the murders, there has been renewed hostility toward Carter by some Chicago aldermen.

Meanwhile, the Forest Park Blue Line terminal was an area of ​​interest for law enforcement agencies for some time. Forest Park village officials said problems at the terminal have been going on for years — and have only gotten worse.

While officials at a news conference Tuesday evening would not confirm whether the victims of the mass shooting were homeless, the Chicago Coalition to End Homelessness said most, if not all, of them are experiencing homelessness.

“Everyone has the right to feel and be safe in our community, regardless of housing status. Many people experiencing homelessness, when faced with multiple poor options, use public transit as a space that offers a form of safety and community,” the organization said in part in a statement. “The fact that a murderer took his own life in this space underscores how failed we have been as a society.”

Foxx said Davis will appear for a detention hearing at the Maybrook Courthouse in Maywood on Wednesday. Prosecutors said they will provide much more information about his criminal record and the facts of the case at Wednesday’s court hearing.