( CNN ) -- Massachusetts investigators said Friday they think they have found the remains of Jeremiah Oliver , a 5-year-old boy who was missing for months before police were called . Though positive identification has not been made , Worcester County District Attorney Joseph D. Early Jr. said the body of a child found wrapped in a blanket inside a duffel bag near a central Massachusetts interstate matches the height and weight of Jeremiah . The case of Jeremiah Oliver was the result of what Massachusetts Department of Children and Families Commissioner Olga Roche called `` a serious failure . '' Roche oversees the state 's social workers , including those assigned to the Oliver household . `` The social worker assigned to this case did not conduct the required in-person , monthly checks on the family , '' Roche said in a statement when the boy was reported missing in December . `` And the supervisor failed to enforce that policy . '' Roche fired both of them almost immediately . The last documentation of an interaction with Jeremiah was in May 2013 , according to Department of Children and Families spokesman Alec Loftus . In June , Loftus said , the social worker was told that Jeremiah had moved to Florida to live with his grandmother , but did not follow up or verify that . The last visit to the home was in November , at which the social worker left behind a business card indicating it would be the Department of Children and Families ' final visit , Loftus said . On December 2 , Jeremiah 's 8-year-old sister told counselors at her elementary school that her mother 's boyfriend , Alberto Sierra , 22 , had abused her , according to a police affidavit . After those statements , the girl and another brother were taken into protective custody , according to the affidavit . When police asked Elsa Oliver , 28 , where her third child , Jeremiah , was , she told them he had moved to Florida , a law enforcement source involved in the investigation told CNN at the time . At a December 13 hearing before a state juvenile judge , Oliver was `` observed to have bruises , disheveled hair , and appeared to have been assaulted , '' according to court documents . She refused to divulge Jeremiah 's whereabouts , according to the source , so she was arrested . In March , Oliver and Sierra , both of whom have been in custody since December , were indicted by a grand jury on charges related to Jeremiah 's disappearance , as well as on charges of child abuse . Calls to the attorneys for both were not immediately returned Friday . An autopsy on the remains found Friday is expected to be completed over the weekend . CNN 's Lawrence Crook III and Dave Stewart contributed to this report .
DA : Child 's body found in duffel bag the size of an Oliver . Jeremiah , 5 , was missing for days before authorities were alerted . Mom , boyfriend were indicted in Massachusetts in his disappearance . Case called ` ` serious failure '' for the Department of Children and Families .