WOODSTOCK, Ill. (AP) — A judge has ruled that a suburban Chicago woman who pleaded guilty in her 5-year-old son’s beating death cannot challenge her conviction and 35-year sentence.

Thirty-nine-year-old JoAnn Cunningham claimed in her petition for post-conviction relief that she was suffering from postpartum depression and psychosis when she killed her son AJ.

McHenry County Judge Robert Wilbrandt ruled Wednesday that the arguments in Cunningham’s petition were “patently without merit.”

Authorities say Cunningham forced AJ to stand in a cold shower for 20 minutes, beat him with the shower head, then put him to bed cold, wet and naked in April 2019.

His body was found wrapped in plastic in a shallow grave near their home in Crystal Lake.