BALTIMORE (WJZ) — A Harford County woman is under arrest on murder in the death of her 3-year-old niece, authorities said Thursday.

Barbara Ann Mumpower, 41, of Belcamp, was taken into custody Wednesday on charges of first-degree murder, child abuse, child neglect and accessory after the fact, the Harford County Sheriff’s Office said.

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Mumpower is the second person charged in the murder of her niece, Maria Barlow, who died last Friday. Randolph James Mack, a 43-year-old Essex man, was arrested the day after the girl’s death.

Mack

Deputies were called to the family’s Ashmead Square home June 3 in response to a report of a child in cardiac arrest. The girl was taken to Upper Chesapeake Medical Center, where she was pronounced dead.

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Based on a preliminary investigation, Mack was charged with first- and second-degree murder, first- and second-degree assault an child abuse, deputies said.

Deputies said the investigation uncovered a “pattern of abuse” at the hands of both Mack and Mumpower, who had custody of the girl and was involved in a relationship with Mack, dating back to early January.

After conferring with the Harford County State’s Attorney’s Office, deputies arrested Mumpower on Wednesday, the day her niece would have turned 4.

Both Mack and Mumpower remain in custody while awaiting court proceedings in the case. While two arrests have been made, deputies said their investigation into Barlow’s death is ongoing.

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Anyone with information about this case is asked to call detectives at 443-409-3154 or Metro Crime Stoppers at 1-866-7LOCKUP.

CBS Baltimore Staff