Police are investigating the death of a 3-year-old boy who was dropped off at University Hospital at Downstate on Sunday by a man and a woman who left before answering any questions. Their relationship to the child is still unknown, according to police sources. Officials say the boy was unconscious and had visible bruising when he arrived at the hospital shortly before noon. He was pronounced dead a short time later. Authorities have not yet determined if foul play was involved. Click here to read more on brooklyn.news12.com.