The McHenry County Coroner says A.J. Freund died of craniocerebral trauma as a result of multiple blunt force injuries.
Police said earlier that the Crystal Lake 5-year-old was forced by his parents into a cold shower and beaten before he died.
His parents, Andrew Freund, Sr. and Joann Cunningham, were both charged with first degree murder, aggravated battery, and failure to report a child death.
Bond for the couple has been set at $5 million each.
At a press conference held Wednesday afternoon, Crystal Lake Police Chief James Black and FBI Special Agent Colin McGuire said they confronted Cunningham and Freund, Sr. after they recovered forensic evidence from cell phone records.
Once presented with the evidence, both parents provided information that lead to the discovery of A.J.’s body, buried in shallow grave, wrapped in plastic.
Authorities have not yet said how A.J. was killed, or how long he was buried.
DCFS confirmed that its investigators have been in repeated contact with Andrew’s family since he was born with opiates in his system in 2013.
Andrew was taken into DCFS custody and placed into a foster home less than a month after he was born. He was returned to his birth parents in June 2015, DCFS officials said.
WGN reports that investigators responded to the home 17 times in five years for allegations of abuse and drug use.
In 2014, a woman alerted police that the tenants in the family home were using heroin after a she found a syringe on the kitchen floor.
In 2018, neighbors reported saying the house had no power, and was surrounded by grass nearly two feet tall.
When police responded to a burglary at the house in December, they reported an “overwhelming” smell of dog feces and urine, and repoted that the door to the house was covered in a brown substance. Police also said “several windows were open or broken.”
Acting Director of DCFS, Marc Smith, released a statement Wednesday, saying, “After a nearly week-long search for missing Andrew ‘A.J.’ Freund, law enforcement officials today confirmed his death. This news is heartbreaking. Protecting vulnerable children who come to our attention is at the core of our mission at DCFS. All of us feel this loss. Our priority is the care and safety of Andrew’s younger sibling. We will continue to cooperate with law enforcement in their ongoing investigation. The Department is committed to conducting a comprehensive review of the entirety of our work with Andrew’s family to understand our shortcomings and to be fully transparent with the public on any steps we are taking to address the issues.”