Man charged in Chicago-area deadly train shooting of 4 people to appear in court

A man has been charged with four counts of first-degree murder after four people were fatally shot on a Chicago Transit Authority train in Forest Park, Illinois, early Monday, officials said. He is due in court on Thursday at 12 p.m. local time.

Rhanni S. Davis, 30, of Chicago, has been charged in their deaths, according to Forest Park, Illinois, police.

Cook County State Attorney Kim Foxx said in a Tuesday press conference that Davis allegedly entered the train car where people were sleeping and "pumped bullets into their bodies." The motive is still under investigation, but authorities believe that this was a random attack.

The Cook County Medical Examiner's Office identified three of the victims, according to ABC affiliate WLS: Adrian Collins, 60, suffered a gunshot wound to the abdomen. Simeon Bihesi, 28, was shot multiple times. Margaret Miller, 64, suffered a gunshot wound to the head.

All three deaths have been classified as homicides. Forest Park police said they are still trying to contact the fourth victim's next of kin.

The Forest Park Police Department received a 911 call about three people shot on a westbound train at the CTA Blue Line station in Forest Park, just west of Chicago, around 5:30 a.m. local time, according to a statement from police.

Authorities cleared the station, finding four victims. Three were pronounced dead on scene and the fourth was taken to Loyola University Medical Center in Maywood, where they died.

Forest Park police, along with CTA security, used video surveillance to help identify the alleged offender. Then, the Chicago Police Department located a suspect who matched the description on a CTA Pink Line train. The subject was taken into custody and a firearm was found, Forest Park police said.

According to Forest Park officials, the shooting appears to have been an isolated incident with no immediate additional threat to the community.

In a statement, the CTA called the incident a "heinous and egregious act of violence" that "should never have occurred, none the less on a public transit train."

"As soon as it was reported, CTA immediately deployed resources to assist the Forest Park Police in their investigation into the matter, including review of all possible security camera footage, which proved to be vital in aiding local enforcement," the statement read.

The CTA commended the Forest Park Police Department and the Chicago Police Department for their rapid response and coordination.

CTA said it will continue to work with local law enforcement regarding the ongoing investigation.

ABC News' Victoria Arancio contributed to this report.