(INSIDE EDITION) Authorities say a Maryland woman pleaded guilty Monday to murdering two of her children and stabbing two others in an attempt to rid them of demons she and her roommate believed had possessed them.
Zakieya Avery -- known as the "exorcism killer" and "demon assassin" -- and her roommate, Monifa Sanford, claimed they attacked her four children in January 2014 after they saw the eyes of the children blackening, according to reports.
Believing that killing the children was the only way to rid them of demons, Avery and Sanford stabbed Avery's 18-month-old son, Norell, more than 20 times, prosecutors said.
Avery's 2-year-old daughter was also killed after being choked and stabbed in the chest and back, authorities said.
Her 5-year-old daughter and 8-year-old son survived the brutal attack, officials said.
Avery's lawyers are expected to argue that she was not criminally responsible for her actions, the Associated Press reported. If a judge agrees, Avery could be sent to a psychiatric hospital.
Sanford was reportedly committed to a psychiatric hospital for "an undetermined amount of time" after being found guilty, but not criminally responsible, to two counts of first-degree murder in January 2015.
The women met in 2013 through their church and became like "sisters," bonding as Avery taught Sanford about demons, WUSA9 reported.
When Sanford began experiencing "demonic shadows and noises" in her father's home and after Avery's husband moved out of their house, the two women moved in together, according to WUSA9.
Their mental states continued to reportedly deteriorate and they isolated themselves and started suspecting inanimate objects and their imaginary boyfriends were possessed.
The night before the children were murdered, a neighbor who works as a mental health evaluator spotted the four children alone in Avery's freezing car. He knocked on the door and after he saw Avery was chanting and responding to internal stimuli, he called the police.
Police responded, but when they knocked on Avery and Sanford's door, music that had been playing inside stopped and the lights were turned off. They contacted Child Protective Services about the incident and decided to come back another time, WUSA9 reported.
Hours later, in the early hours of January 17, 2014, Avery allegedly woke Sanford and told her that everyone was dead and only their spirits remained.
They attacked the children and then Avery reportedly turned on Sanford,stabbing her and choking her as she showered.
Sanford managed to get a knife and confronted Avery, but Avery gained control of the second weapon and continued to attack Sanford, according to reports.
After the attack, they showered and discarded the clothes they wore during the attacks and threw the knives out a window, authorities said.
Police responded to a report of suspicious activity at the home about 9:40 a.m. Avery tried to flee with her oldest son after making him shower and wrapping him in a bedsheet.
WUSA9 reported that after the murders, Sanford told police, "I'm glad the children are in heaven, but I miss them."