A mother brutally killed her 7-year-old son Thursday while other members of the family were at home, police say.

Hanane Mouhib decapitated her son, Abraham E. Cardenas, in what police called an "isolated incident" that surprised five other family members who were home during the slaying, according to the Democrat & Chronicle.

"There's absolutely no explanation for us," Monroe County Sheriff Todd Baxter told the Democrat & Chronicle. "The word 'evil' comes to mind … this is a mother who took her son's life."

The relatives, including the boy’s father, a 10-year-old brother and grandmother, were not injured.

Mouhib was arrested and charged with second-degree murder. She pleaded not guilty and is being held in jail without bail.