What happens to Lucy when Haley takes her baby away while she is sleeping in order to give him to a white man that purchased the child?

After Haley takes her child, Lucy jumps overboard and drowns herself during the night.

At midnight, Tom waked, with a sudden start. Something black passed quickly by him to the side of the boat, and he heard a splash in the water. No one else saw or heard anything. He raised his head,—the woman’s place was vacant! He got up, and sought about him in vain. The poor bleeding heart was still, at last, and the river rippled and dimpled just as brightly as if it had not closed above it.