Deputy County Attorney Joel Thompson said authorities have yet to determine how or when the boy died. An autopsy is being conducted. According to court records, ManyWhiteHorses told police the boy's death was an accident, and that she placed his body in the car's trunk on May 29.
ManyWhiteHorses was being held on $250,000 bail. During a brief court hearing, she appeared without an attorney and was provided forms for a public defender.
Personnel at the Cascade County Detention Center turned away a reporter's attempt to speak with her Monday because it was outside visiting hours.
ManyWhiteHorses was first arrested July 21, after authorities said she was driving erratically. As police attempted to pull her over, she drove through several stoplights and crashed into a parked car. Her 11-year-old daughter was in the back seat and, unknown to police, the toddler's body was apparently in the trunk, authorities said.
Police officers did not search the trunk, and the car was towed. ManyWhiteHorses was arrested, and child welfare officials began looking into placing the daughter into state custody.
ManyWhiteHorses was given misdemeanor citations in connection with the crash and later released from jail. Authorities said she did not retrieve her car even though she was free to do so.
Child welfare officials moved for custody of the daughter in August and were trying to determine the boy's whereabouts.
During the investigation, authorities learned that ManyWhiteHorses told relatives the state had taken the toddler long ago, that state officials were told initially the child was in Browning and then later that he was in Portland, Ore.
"Her stories varied based upon who she was talking to," said police Detective Bruce McDermott.
Police were brought into the case last week after child welfare agents could not verify the toddler's location. A short time later, ManyWhiteHorses told officers the toddler, who had autism, had died in late May, according to court records. ManyWhiteHorses told police she put the body in the trunk, wrapped in a blanket inside a garbage bag, the affidavit said.
Officers went to the wrecking yard and found the boy's body in the trunk, authorities said.
ManyWhiteHorses' aunt, Ernestine Small, said she had taken care of the two children during ManyWhiteHorses' prior run-ins with the law. Small had been hoping to take custody again this summer, but was told by ManyWhiteHorses that the toddler had been placed in foster care.
"Nobody expected this," Small said in an interview at the courthouse. "I know she gets violent, but never thought she would do this to her baby."
Both prosecutors and police said the officers followed the law by not searching the trunk after ManyWhiteHorses' July 21 arrest, saying legal cause and a search warrant would have been needed.
"Police had no reason to believe there was anything of evidentiary value in the trunk," McDermott said.
Small, ManyWhiteHorses' aunt, said the officers could not have known to search the trunk.
"Why would they?" she said.