The children's mother, Zakieya Latrice Avery, 28, of the 19000 block of Cherry Bend Drive, was charged in January with murder and attempted murder in the stabbings of her four children.
Monifa Denise Sanford, 21, of the same address, faced the same charges in the case.
Both women were indicted Thursday on two counts of first-degree murder and two counts of attempted murder, according to WTOP.
When police were called to their home on Jan. 17, officials found two children—identified as 1-year-old Norrell Harris and 2-year-old Zayna Harris—dead in an upstairs bedroom. The Office of the Chief Medical Examiner determined the deaths were homicide by multiple stab wounds.
Two other children—identified as 5-year-old Taniya Harris and 8-year-old Martello Harris—were found seriously and critically injured at the scene.
Police were called to the house after a neighbor saw a vehicle with a knife next to it and the door open. The vehicle was bloody and contained house keys that police used to get into the home, according to WTOP.
Avery was captured by police as she tried to flee out the back door of her residence, according to police, who said the women believed they were performing an exorcism on the children.
When interviewed by police, Avery and Sanford reportedly said they saw the children’s eyes blacken as demons entered their bodies and jumped from one child to the next, from youngest to oldest. They claimed the exorcism was needed to cast out the demons.
"Both defendants alleged that the demon leapt from the body of the last child into Mrs. Avery and then back to Sanford," Montgomery County State's Attorney John McCarthy said during a January hearing. "She was able to fight off that demon."
Sanford was also stabbed, though it was unclear whether she was stabbed by Avery or if her wounds were self-inflicted, police said.
Both women were ordered to seek mental health evaluations at Clifton T. Perkins Hospital in Jessup.
Currently, Avery and Sanford are being held without bond, according to WUSA 9, and if convicted, they could face a maximum sentence of life in prison.