Troopers say 24-year-old Leanna Norris of Auburn was taken into custody Wednesday following her release from a medical center where she was receiving treatment.
The body of her daughter, Loh Grenda, was discovered around 3 a.m. June 23 in her mother's car in Stetson. Police believe the girl was killed in the neighboring town of Newport.
Norris was indicted last week on a murder charge.
She was taken to the Penobscot County Jail and is due to be arraigned Friday. It was unclear Wednesday if she'd retained a lawyer.
Autopsy results haven't been released, but the state medical examiner's office declared that the girl's death was a homicide.