Monroe County Sheriff Todd Baxter called it an extreme, horrific crime scene.
Deputies responded to a call at 5499 South Lake Road in Sweden last night for a suicidal female with a knife who refused to surrender.
Baxter says deputies needed to use pepper spray and a taser to take her into custody.
Two other adults and a child were in the home at the time, and in an adjacent room deputies discovered a 7-year old boy, Abraham Cardenas.
"Abraham suffered a stab wound to his back, and a severe stab wound to his neck causing his head to become disengaged from his body," he said. "This is a tragedy. This is what occurs sometimes in our world. We are human beings and sometimes we create horrific scenarios to have to live through and process, and this is one of them. I don't think you'll ever be able to put words on an explanation of what occurred last night. None of us could."
36-year old Hanane Mouhib has been charged with second degree murder and is being held without bail.
Baxter says deputies responded to a call from a female seeking assistance at Mouhib's address on two previous occasions.
One resulted in police conducting a mental hygiene transport to Rochester General Hospital, where Mouhib stayed for over two weeks.
Abraham attended the Brockport Central School System.
School officials say counselors will be available over the weekend and Monday at the school.