On Monday, the Department of Children and Families released public records documenting a history between Dontrell Melvin's family and the agency. Click here to view them.

Dontrell Melvin was last seen in July 2011, and human remains have been found behind the house were his parents used to live. The medical examiner is conducting DNA tests to identify the remains.

In October, a Hallandale Beach Police Officer called a state child abuse hotline to report that Brittney Sierra, the boy's mother, said she had not seen her son in more than a year.

"She said she hasn't seen the baby in -- since July of 2011," the officer said in the recorded conversation.

The hotline operator asked what was going on with the case.

"I was just told that my sergeant wanted me to contact you to let you know. I mean, she hasn't seen the baby since July of 2011. I mean, I don't know how persistent she was in seeing her child. She still talks on and off with the father but every time she asks about the baby, he is just always making excuses and never brings the baby by. She doesn't even know, I mean, whether the baby is even alive or not," the officer said.

The call was documented but "screened out."

DCF said missing child cases are not under their purview and pointed to the police department as the agency responsible for investigating missing child cases.

Police said the October inquiry was a custody issue, not a missing child case.

Documents released by DCF show subsequent anonymous calls to the child abuse hotline reporting drug use in the home of Sierra's mother, where she was living with her other children. Another caller reported that some of the children were left unsupervised, and that at least one child wore days-old clothes and smelled.

DCF Secretary David Wilkins issued a statement regarding the release of the documents Monday, saying: "This entire Department and every employee is deeply saddened each time we hear about the death of an innocent child. We will continue to work closely with the Hallandale Beach Police Department and the Broward County Sheriff's Office on their respective investigations.

"These records contain the interaction between child welfare officials and Dontrell Melvin. Dontrell's siblings are safe in the custody of our agency. In addition, four other minor children in the household have been taken into DCF custody to ensure their safety and well-being.

"Questions have been asked regarding the October 2012 call to the Florida Abuse Hotline from the Hallandale police officer. The call clearly indicates a missing child report, which this agency does not have the legal authority to investigate. Missing children and cases of criminal activity are under the authority of law enforcement unless child abuse or neglect is suspected. There was no allegation of abuse or neglect of this child in the October 2012 Hotline report. However, the information collected during this call was instrumental to the January 2 investigation. The current child protective investigator used information gathered in the previous Hotline report to determine that the child could not be located and notified law enforcement.

"We would like to thank the Broward County Sheriff's Office and the Hallandale Beach Police Department for their assistance when the most recent child protective investigation became a criminal investigation. Our thoughts and prayers are with the siblings and other family members of Dontrell."

Search continues for fourth day

For the fourth day, crime scene technicians searched a home where remains believed to be human were found last week in connection with a death investigation.

Investigators brought in heavy equipment Monday to sift through dirt where they found remains last Friday. Hallandale Beach Police Chief Dwayne Flournoy said a partial skull and several bones were found buried about a foot deep.

Hallandale Beach search

Investigators believe the remains are 5-month-old Dontrell Melvin.

"Yeah, sifter. They were sifting dirt, sifting through it, and I guess that's how they were taking out the evidence, whatever they needed," said Natalie Garrido. "They were really looking for stuff."

No one reported Melvin missing for 18 months.

"I can't even imagine that someone would do something like that," said Garrido.

Friend: Boy's parents had rocky relationship

Melvin's parents, Brittney Sierra and Calvin Melvin, Jr., were arrested Friday. Both are charged with child neglect.

Flournoy said Melvin and Sierra separately advised police to search the same area. He added they blamed each other for hurting the child.