ATLANTA -- A criminal investigation is underway in the Bobbi Kristina Brown case with her boyfriend at the center of it.
Brown's grandmother, Cissy Houston, arrived at the hospital in Atlanta yesterday.
Brown is in a medically-induced coma.
TMZ is reporting that police are looking into a fight Brown may have had with her boyfriend just before she was found face-down in a bathtub full of water.
Meantime, family members continue to arrive at the Atlanta area hospital.