Ida Helen Brockman, 30, is charged with one count of murder and one count of child abuse resulting in death, while her boyfriend, Malachi Whalen, 29, is charged with one count of murder, one count of torture and one count of child abuse resulting in death.
Court papers identify the victim as Amaiya D.
Hawthorne police officers responded last Thursday to Martin Luther King Jr. Community Hospital regarding a possible child abuse/child dead call, according to a news release from the Los Angeles County Sheriff's Department.
The child was pronounced dead at the hospital after she was brought to the emergency room unresponsive by the mother and her boyfriend, authorities said.
According to investigators, the couple's account of what happened were inconsistent with the child's fatal injuries.
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The investigation - in which sheriff's homicide detectives and the District Attorney's Office have also been involved - subsequently led police officers and detectives to the "crime scene" at an apartment in the 3000 block of El Segundo Boulevard, where the girl lived with her mother and the mother's boyfriend, LASD said.
Residents were shocked to find out their neighbors had been arrested for the 7-year-old child's death.
"At first I didn't want to believe it. I was hoping that something else happened, but I hope that justice is dished out - to whoever deserves it - for that baby," James Western, who said he's acquainted with Whalen, told Eyewitness News.
Neighbors say Amaiya was a sweet and smart girl, and that it's still hard to believe she was allegedly tortured and murdered at the apartment unit.
"You start to think of what was going on - should I have been more aware of something so close to me?" neighbor Kenneth Huerta said.
The two suspects are set to be arraigned Sept. 23 at the Airport Courthouse, according to the L.A. County District Attorney's Office.
Whalen remains in custody, with his bail set at $2 million. Brockman's bail has been set at $600,000.
City News Service contributed to this report.