Police in San Luis Obispo, Calif., are following the "most promising lead we've had in years" in the hopes of finding some trace of a California Polytechnic State University freshman who vanished 20 years ago. Human decomposition dogs "and other information" led police and the FBI to three sites on the campus—including one spot marked by the "P" in a giant hillside sign for Cal Poly—which will now be excavated over four days, reports the Los Angeles Times. Without elaborating, police say evidence "strongly suggests" Kristin Smart may be buried at one of the sites, per the San Luis Obispo Tribune. The 19-year-old student disappeared after leaving an off-campus party in the early hours of May 25, 1996.
A witness told police that Paul Flores, 19, offered to walk Smart home after she'd apparently passed out. Flores—who's considered a person of interest but has never been charged due to a lack of evidence, police say—claims he dropped Smart off near her dorm, though the Tribune notes four cadaver dogs reacted separately to Flores' dorm room, focusing on a mattress and wastebasket, after he moved out in June 1996. The Smart family has sued Flores in civil court, though searches at properties linked to the Flores family have turned up no sign of Smart. "We're not sure where this is going to take us," a sheriff tells CBS News of the new dig. "Obviously, we want to be optimistic as possible." (The FBI is hunting a dormant serial killer.)