but michelle herndon's case was different. >> at the end of the autopsy, i really had no idea.idn't find anything -- anything slightly wrong whatsoever. >> to find somebody that's deceased without any indication of what caused them to die, especially somebody that's that young, was highly unusual. >> the medical examiner estimated that michelle died about 24 hours before her body was found. so investigators interviewed everyone who was with michelle during that timeframe. they also checked the alibis of those closest to michelle, including her fiance. >> jason, squeaky clean. jason had an alibi of being at work and was quickly removed as a potential suspect. >> then the medical examiner took a closer look at something on michelle's left arm. a tiny mark, smaller than most needle marks. >> we needed to find the explanation for that puncture wound. and there could be a very legitimate explanation for it. >> but michelle's personal physician said she didn't have any blood drawn before her death or receive any injections. so the medical examiner told investigators to widen their se

it's also time for thousands of students to get back to their studies. 24-year-old michelle herndon wasar.