James Eric Davis Jr., 19, was taken to Isabella County Jail. On Tuesday, he appeared in the courtroom via video monitor for his arraignment.
Davis, Jr. is held on a $1 million bond and is charged with two counts of murder and a weapons charge.
Officials said he gunned down his father, James Eric Davis Sr., and his mother, Diva Davis, as they arrived to pick him up.
Davis Sr. had been a longtime member of the Illinois Army National Guard, serving in the Iraq War and later as a recruiter, according to Illinois National Guard spokesman Lt. Col. Brad Leighton.
Their memorial services are scheduled for this weekend. A wake will be held from 4 to 8 p.m. at the Johnson Funeral Home at 5838 W. Division Street and funeral services will be held on Saturday, a family spokesperson said.
Representatives for the family said that they still have many questions, including why Davis, Jr. is still hospitalized and what caused him to commit the murder if he is responsible for it.
Investigators have not reported whether drugs were found in Davis, Jr.'s system.
A spokesperson for the Davis family said in a statement, "On behalf of the Davis family they would like to thank the Bellwood Police Department and American Airlines for the support that they have extended to the family. They would also like to thank the friends and coworkers of Sergeant Davis and Mrs. Davis for all of the prayers and condolences that they have extended. In this very difficult time, the Davis family wants to express their love and support for Eric Junior whom they love and for him to know that he has not been abandoned. Further, they want it known that Eric Junior is their main focus. They also ask for privacy at this most difficult time."
The suspect's attorney said his next court appearance has been set for March 16.