The Illinois parents accused of killing their 5-year-old son forced him to stay in a cold shower and viciously beat him, according to court documents.

Andrew Freund Sr., 60, and Joann Cunningham, 35, were charged Wednesday with murder after Andrew “AJ” Freund was buried about 7 miles away from their Crystal Lake home, the Chicago Tribune reported.

The couple reported their son missing from his bed on April 18 — around three days after authorities suspect they killed the child, officials said.

His cause of death hasn’t been released pending an autopsy. But investigators said the pair left him in a frigid shower for “an extended period of time” and may have struck the young child, likely knowing their actions would kill him, according to court documents.

The Illinois Department of Children and Family Services said they paid several visits to the family’s home since AJ was born in 2013.

Police arrested the pair Wednesday morning after finding incriminating information on a cellphone.

Charges for first-degree murder were filed against both the parents. Cunningham was also charged with aggravated battery, aggravated domestic battery and failure to report a missing child or child death.

Freund Sr. faces charges for aggravated battery, aggravated domestic battery, concealment of a homicidal death and failure to report a missing child or death.