TONIGHT AT 10 P.M.: Brad Edwards goes over, step by step, what happened the morning 5-year-old A.J. Freund was reported missing – and discovers a potential motive for the boy’s murder.

CHICAGO (CBS) — The CBS 2 Investigators are digging into a case that riveted the nation earlier this year.

JoAnn Cunningham is accused of murdering her young son, 5-year-old A.J. Freund. Over a series of a half dozen recorded conversations and even more letters, CBS 2’s Brad Edwards asked her everything.

“I would rather kill myself than hurt my family,” Cunningham said tearfully in one of the calls. “I’d rather kill myself than hurt anybody.”

Before that, it started with a missed call. It was from the 815 area code and included a voicemail that identified the caller as JoAnn Cunningham – an inmate at the McHenry County Jail.

So started a series of communications between Cunningham and Edwards.

Edwards asked to record the calls, and Cunningham said yes. That was the most necessary answer for us to chart how Cunningham, maybe the most loathed mother in America, pictures it all happened.

“I feel like this is getting worse in here for me the more I talk to you,” she said.

RELATED: A.J. Freund’s Parents Plead Not Guilty To Murder; Attorney Seeks Psychological Evaluation For Dad

Cunningham and her ex-boyfriend, Andrew “Drew” Freund, stand accused of murdering their 5-year-old son, A.J.

Police and prosecutors have alleged A.J.’s parents forced him into a cold shower as punishment for soiling his clothes and severely beat him on April 15.

His father later found him dead in his bed at their home in Crystal Lake and buried him in a shallow grave. A.J.’s parents falsely reported him missing three days later.

RELATED: ‘Maybe Mommy Didn’t Mean To Hurt Me’; A.J. Freund Told Doctor About Mysterious Bruise Five Months Before His Death

For days, the community prayed A.J. was alive. But police found A.J.’s body wrapped in plastic in a shallow grave in Woodstock on April 24 and charged both of his parents with murder.

Soon after Cunningham’s arrest, in an effort to draft a proposal, Edwards wrote her, simply wanting to know how she would answer.

Edwards: “Did you kill A.J.?”

Cunningham: “No. I would never hurt my children.”

Edwards: “Now, you say that, but some people will say you used drugs while you were pregnant.”

Cunningham: “I know, and that’s something I cannot take back.”

Cunningham also said: “If it’s Drew, then he needs to grow some balls and he needs to tell them so everyone isn’t suffering. You know, I’m scared.”

RELATED: A.J. Freund Case: DCFS Timeline Raises Questions About Neglect Investigation Four Months Before Boy’s Death