One of two women involved in the killing of two children and attempted killing of two others pleaded guilty to the charges against her in a Maryland courtroom on Friday. 

Monifah Sanford of Germantown was found guilty but not criminally responsible on two counts of first-degree murder and two counts of attempted first-degree murder. 

Sanford and her roommate, Zakieya Avery, attacked Avery's four children in January 2014 as part of an alleged exorcism. 

According to court documents, Sanford suffered from hallucinations, and believed that the children were demons. She also believed that one of the children was Satan, and that he was going to "kill the babies. If she wanted them to go to heaven, she had to do it herself."

"She believed that she had been initiated into this group of demon assassins," her attorney, David Felsen, explained. 

Sanford and Avery reportedly watched YouTube videos involving demons, and danced to ward them off. 

"They had believed that inanimate objects had been possessed, there were demons in their house, that they had been possessed individually, that at other times, the children had been possessed," Felsen said

The women choked and stabbed 18-month-old Norell and his two-year-old sister Zyana until the toddlers died. An eight-year-old boy and five-year-old girl were also attacked, but survived. 

Sanford told police, "I'm glad the children are in heaven, but I miss them."

Under a plea agreement approved by Montgomery County Judge Cheryl McCally, Sanford, 21, was committed to Clifton T. Perkins Mental Hospital. Avery's trial is expected to begin later this year.