By Bobby Sisk, WBZ-TV

FITCHBURG (CBS) – A 5-year-old Fitchburg boy hasn’t been seen since September 14th. Police just found out about Jeremiah Oliver’s disappearance on Friday when his sister revealed concerns to a teacher and then a counselor at school who notified police.

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“Immediately State Police detectives assigned to the Worcester DA’s office and Fitchburg Police detectives responded to 276 Kimball street. A search warrant was executed,” said Worcester County DA Joseph Early. Early would not give specifics on what the little girl said or what was found in the apartment, but it was enough to bring charges against the children’s mother and her boyfriend. “I don’t want to speculate but we are treating this as a homicide investigation based on the facts that we have,” he said.

The boyfriend, 22-year-old Alberto Sierra, was arrested Saturday morning and charged with harming the child. He’s facing two counts of assault and battery with a dangerous weapon (a knife) and two counts of assault and battery of a child causing bodily injury. One of the charges involves an assault on the children’s mother.

The two charges related to a child involve Jeremiah and his sister, the one who ended up tipping off police. DA Early would not say if the sister and another brother saw what happened to Jeremiah. “I can’t get too much into that, it is part of the investigation but we did get enough information from family members to bring these charges,” he said.

Elsa Oliver was arrested Monday on two counts of reckless endangerment of a child and two counts of accessory after the fact of a felony. She’ll be in Fitchburg District Court for an arraignment on Tuesday. “There is a court order for the mother to produce Jeremiah and he has not been produced and we anticipate a contempt hearing on that in the juvenile court,” Early said. The juvenile court hearing will come later. He confirmed both Oliver and Sierra were known to authorities.

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A neighbor in the building where Oliver and the children lived said she heard loud noises last Thursday night, the night before police showed up. She’d seen the two older children, ages 7 and 8, but in her two months living there, had never seen Jeremiah. She had spotted the boyfriend, Sierra coming and going.

Jeremiah has brown hair and brown eyes and stands three feet, four inches tall. Early is asking for the public’s help in the case and is thankful Jeremiah’s sister came forward.

“We have a lot of feelings with her and her brother and this will come out later but yea, that little girl showed a lot of courage showing what she did,” he said.

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

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