For many, an exorcism is just something you see in the movies or read about in books.
But, for some, it is a very real ceremony they believe will banish evil demons out of human bodies.
It is one of organized religion's most controversial practices and, unfortunately, often ends tragically as it did this weekend.
Police in Germantown, Maryland report that on Friday, Zakieya Latrice Avery killed two of her own children during what they believe was an exorcism.
One-year-old Norell Harris and his 2-year-old sister Zyana were found stabbed to death in their home.
A 5-year-old sister, Taniya, and 8-year-old brother, Martello, were also injured during the alleged ceremony and remain in the hospital.
One other woman, Monifa Denise Sanford, was also at the scene and has been charged with two counts of first-degree murder and two counts of attempted murder, the same as the childrens' mother.
OutFront: Director of the Major Crimes Division at Montgomery County Police Department, Captain Marcus Jones.