. >> 18-year-old sonja larson was found murdered. >> 17-year-old christina powell. >> 18-year-old christa hoyt. ♪ early this morning ♪ >> three young women, all students have been found. >> there was a mutilation -- >> manny taboada, tracy paules -- >> brutally murdered at their apartment. ♪ i said, hey, lord save me now ♪ >> this was the ultimate nightmare for parents who are sending their kids off to college. in a space of, you know, three days, one after another after another, students in apartments being killed, totally vulnerable. >> now that the death toll has reached five, students are talking of returning home. >> i'm terrified. i couldn't sleep last night. >> it's really scary. >> what's the worst that could happen? well, this was the worst that could happen. ♪ me and the devil ♪ >> they have a serial killer -- >> serial killer is on the loose. >> i'm john donvan. and in the early '90s, abc news sent me to gainesville, florida, to cover the story of the gainesville student murders, one of the most horrifying stories that i had ever covered. >> today people walk and wonder if he w