(CNN) The Illinois Department of Children and Family Services' (DCFS) involvement with the family of Andrew "AJ" Freund predated his birth five years ago.

Child welfare authorities on Friday released a four-page summary of the agency's contact with AJ's parents, Andrew Freund Sr., 60, and JoAnn Cunningham, 36.

JoAnn Cunningham and Andrew Freund Sr. are charged in the death of their son AJ.

The DCFS summary revealed a litany of child welfare hotline calls about AJ's troubled homelife, reports of squalid living conditions and drug abuse by his parents. When AJ was born on October 13, 2013, mother and child tested positive for opiates. The boy was removed from the home but returned eight months later after his father and mother took parenting classes and entered a drug treatment program.

In December, the boy told a doctor that the family dog caused a large bruise on his hip. But the physician let a DCFS investigator know that AJ also told him, "Maybe someone hit me with a belt. Maybe mommy didn't mean to hurt me," according to the agency.

In January, the case was closed for lack of evidence. Seven months earlier, another investigation into a report of "odd bruising" on AJ's face was also closed. The agency determined the report to be unfounded.

Last week, DCFS received yet another hotline call alleging neglect and inadequate supervision at the home. The call came on the same day AJ's parents reported him missing. Information from the couple ultimately led to the recovery of his body in Woodstock, about 10 miles from their home in Crystal Lake, police said.

DCFS said it was reviewing its handling of cases involving AJ's family. A caseworker and supervisor have been placed on administrative duty with no casework responsibilities during the review. The agency said it will also review all cases handled by the two employees.

Mourners gather at a vigil.

"As we move forward, we will be fully transparent with the public as we seek to address any possible shortcomings in this incident and understand how we can better serve the state's vulnerable children and families," DCFS said in the summary released Friday.

Here's what we know about the department's interaction with AJ's family, based on the DCFS summary of its records, reports and documents:

June 7, 2012 -- DCFS received a hotline call alleging inadequate supervision: Cunningham was accused of abusing prescription drugs and neglecting her foster child. The report was unfounded and expunged.

December 24, 2012 -- Another hotline call alleged "environmental neglect and injurious environment," referring to Cunningham's eldest son, who is now 18 and lives with another family. She was accused of abusing prescription drugs and having mental health issues. The report was unfounded and expunged.

October 16, 2013 -- A hotline report alleged "substance misuse by neglect" after Cunningham gave birth to AJ two days earlier. The boy and his mother tested positive for opiates and benzodiazepines. AJ was removed from his mother's home during the investigation.

November 12, 2013 -- DCFS took protective custody of AJ.

November 14, 2013 -- A juvenile court granted DCFS temporary custody of AJ. The Youth Service Bureau of Illinois provided services to the boy and his parents.

The couple participated in parenting classes, drug treatment and methadone maintenance and individual counseling.

June 2015 -- A judge ordered AJ returned to his mother.

June 2015 to March 2016 -- A Youth Service Bureau worker made 17 unannounced visits to the home. The worker did not observe signs of abuse or neglect.

June 2015 to April 2016 -- A Youth Service Bureau worker made nine scheduled visits to the home. No signs of abuse or neglect were observed.

April 2016 -- AJ's juvenile court case was closed.

AJ Freund was 5.

March 21, 2018 -- A hotline report alleged "substantial risk of physical injury/injurious environment and environment neglect" against AJ's parents. The report said Cunningham was brought to an emergency room after being found unresponsive in a car. AJ was observed at the hospital with "odd bruising on his face."

March 2018 to April 2018 -- A DCFS investigator contacted the parents three times in unsuccessful attempts to see the children.

April 25, 2018 -- A child welfare investigator met with Cunningham, AJ and his younger brother. Cunningham was interviewed while the boys played in the driveway of the home. An investigator observed the boys to be clean and found no signs of maltreatment

May 17, 2018 -- An investigator completed a final safety assessment of the home. The boys were clean and dressed appropriately. Cunningham reported a history of drug use and said she was in drug treatment. The home was clean, neat and adequately furnished.

May 18, 2018 -- An investigator verified Cunningham's participation in drug treatment. The March report was unfounded and the investigation closed.

December 18, 2018 -- A hotline report alleged "environmental neglect as to both boys and cuts, welts and bruises" on AJ. After being called to the home, police observed a large bruise on AJ's hip. Police reported the "ceiling falling down, the floor torn up, and the kids' bedroom smelled of dog urine." Cunningham was arrested for driving on a suspended license. The boys were placed in protective custody.

A DCFS investigator interviewed the boys. The younger brother would not talk to the investigator. The child appeared healthy and well cared for. AJ said he got the bruise when the family dog pawed him.

Cunningham told the investigator they were remodeling the home. She admitted to the presence of dog feces in the house.

She was bailed out and requested to be tested for drugs. The boys were returned home.

An emergency room physician could not determine how AJ's injury occurred, saying it could have been caused by "a dog, belt or a football."

But the doctor was concerned that AJ said "maybe someone hit me with a belt. Maybe mommy didn't mean to hurt me." The father picked up the children at the hospital. He was asked to remain in the home as a safety precaution.

December 19, 2018 -- An investigator conducted an unannounced home visit. The living room and dining room were cluttered with clothes and toys. The kitchen was clean. The floor was missing tile. The ceiling was intact. The investigator sensed a slight odor of dog urine. No feces or urine was observed on the floor. The father denied any corporal punishment. He said Cunningham was not using drugs.

December 20, 2018 -- A DCFS investigator spoke with a previous investigator about her case and findings.

January 4, 2019 -- The child welfare agency determined that the allegation of "cuts, welt and bruises" was unfounded due to lack of evidence.

January 18, 2019 -- Police were called to the home. AJ was reported missing and DCFS received a hotline report that alleged environmental neglect and inadequate supervision. Police observed the home to have "ripped up floors, food lying around and clothes/garbage everywhere."

DCFS took protective custody of AJ's younger brother. He was placed with a licensed foster parent. The boy appeared healthy and showed no obvious visible signs of abuse or neglect during a medical examination.

April 24, 2019 -- Police found AJ's body. They arrested Cunningham and AJ's father for murder and other charges related to his death.