The Bathhouse Secret of Sam

When I was five, I used the family's washing tub to bathe Anna, and to prevent her from catching a cold, I vigorously stoked the fire beneath to keep it blazing.
Midway through, I went out to use the outhouse. When I returned, Anna had vanished from the tub.
Not even a single strand of hair remained.
The next day, Linda was handcuffed and taken away by the police.
The villagers all said Linda had killed Anna.