FITCHBURG, Mass. (WHDH) — Five-year-old Jeremiah Oliver was reported missing on Friday, but relatives say they haven’t seen the child since September.

Investigators immediately searched the home on Kimball Street in Fitchburg and quickly arrested the boy's mother and her boyfriend.

"I've been here for two months. And in the two months I've been here, I've never seen them,” Ada Santos, a neighbor, said.

District Attorney Joseph D. Early Jr. said they learned of the Jeremiah Oliver's disappearance after his 7-year-old sister told a teacher at school.

"She is a courageous little girl. Our feelings are with her and her little brother. This will come out later but that little girl showed a lot of courage doing what she did,” Early Said.

Police are treating this as a possible homicide and will hold the mother in contempt if she does not produce the child immediately.

"This investigation is in its infancy. We need the public's help. We're asking anyone that has any information at all to bring that information to the state police assigned to the Worcester DA's office and the Fitchburg Police,” Early said.

The Department of Children and Families is now taking action. A social worker and his supervisor were fired on Tuesday in what the department calls a “serious failure” in the case.

Elsa Oliver, Jeremiah's 28-year-old mother, was arrested Monday on two counts of reckless endangerment of a child and two counts of accessory after the fact. She was arraigned Tuesday afternoon and is being held without bail.

Alberto L. Sierra, 22, Oliver's boyfriend, was arraigned Monday in Fitchburg District Court on two counts of assault and battery with a dangerous weapon and two counts of assault and battery on a child causing bodily injury.

The sister also stated that her mother's boyfriend assaulted her.

Jeremiah’s two siblings have been taken from his mother and are now in the care of the state.

The family just wants him returned home safe.

"Somebody help us bring him back home where he belongs. Help us please," said Sandrino Oliver, the missing boy's uncle.

Anyone with information about the boy is asked to call the State Police Detectives (508-832-9124) or Fitchburg Police (978-345-9648).

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