PRAIRIEVILLE, La. -- Lauren Roberts was riding in a car with her aunt, Daina Sancho, to Blockbuster one day last summer when Sancho said, "Lauren, I have something to tell you. I'm in love with I.V." Daina was a 41-year-old mother of two. I.V., the nickname for Irwin Vincent O'Rourke III, was only 13 years old. It was a good thing, Roberts said, that she wasn't driving, because the news came as a shock. "I told her to be careful," said Roberts, a slender 17-year-old redhead and mother of a 1-year-old baby girl. "I didn't want her to get in...