The Peoria County Coroner said the autopsy shows blunt force head trauma, and it does not appear to be an accident.
The Department of Child and Family Services said they first investigated the mother for a separate incident in May of this year but did not find anything.
They are now investigating Antonio's mother, Ashley Lohman, and her boyfriend, Russell Smith, for possible neglect.
Unfortunately, there's nothing new about neglect and abuse.
"Nationally, there are about 1,600 or so deaths a year in children due to abuse or neglect, so that's about five children every day who die from abuse or neglect," Pediatric Resource Center’s Medical Director Dr. Channing Petrak said.
Children's Hospital of Illinois sees about 10-12 infant deaths a year due to neglect or abuse and officials remind everyone help is out there.
"We all know that sometimes children can be frustrating, we know that it's tiring to take care of young children because that's where we do see the fatalities are in the much younger children under the age of four," Dr. Petrak said.
But there are avenues for assistance.
“To my knowledge, there's no child that's ever cried them self to death, so you know, just take a step back and take a breath is certainly advisable," Peoria Police’s Assistant Chief Mike Eddlemon said.
"It's okay to ask for help. It is always okay to ask for help from someone: a family member, a neighbor, it doesn't matter, but ask for help. And that's a much better outcome for everybody," Dr. Petrak said.
Antonio had three older siblings and DCFS is monitoring them as they stay with a relative.
Police are also investigating the death. They have conducted many interviews but do not have anyone in custody as of yet.
Copyright 2015 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.