Three of four family members who sustained blunt force trauma injuries during an attack inside a Smyrna home remain hospitalized Friday. According to police, 45-year-old Brian Gum allegedly attacked his 72-year-old father, a 13-year-old boy and an 11-year-old girl inside the home located on One Mile Lane Thursday night. Authorities reported the teenage boy was able to defend himself and his family members from Gum. "It appears the boy stopped the attack and potentially saved the lives of his grandfather and sister," Sheriff Robert Arnold said.Gum, his father and the girl all remain hospitalized at Vanderbilt University Medical Center in Nashville. Their conditions were not immediately released. The teenage boy has since been treated and released at StoneCrest Medical Center in Smyrna. Detectives remain tightlipped on what may have led to the attack. Johl Whitaker lives next door to the family and told News 2 he was surprised to learn of the violent crime. "As far as we could tell, they were just really nice people and nothing out of the ordinary," he said, adding, "at least not until last night."Whitaker doesn't know exactly what transpired Thursday night be he hopes their nightmare ends soon."We've just been praying for them. At this point and time that's all we can do," he saidThe investigation is ongoing.