San Luis Obispo County investigators have renewed their search for the remains of Kristin Smart — the Cal Poly student who disappeared nearly 30 years ago — after soil samples collected at the Arroyo Grande home of convicted killer Paul Flores' mother showed signs of human decomposition.
On Wednesday, May 6, 2026, the San Luis Obispo County Sheriff's Office served a search warrant at the East Branch Street home of Susan Flores, whose son was convicted of Smart's first-degree murder in 2022 and sentenced to 25 years to life in prison the following year.
The warrant, described by Sheriff Ian Parkinson as a "kick-out" warrant, required Susan Flores to vacate the property for the duration of the search. She has never faced criminal charges in the case, according to CNN.
During a press conference on Friday, May 8, Sheriff Parkinson confirmed that soil samples collected from Susan Flores' property and a neighboring yard showed signs of decomposition, though he stopped short of confirming the samples were linked to Smart.
"We believe that based on what we're looking at evidence-wise, scientific evidence that a human remains were there at one time were still there," Parkinson said, adding, "We are not leaving that house until we've checked everything."
The search was triggered by a 2023 soil vapor sampling study conducted by a group of scientists — including environmental engineer Tim Nelligan, environmental chemist Steve Hoyt, and retired FBI forensic scientist Brian Eckenrode — who detected volatile organic compounds near the back fence of a neighboring property that borders Susan Flores' yard.
The technology, which uses soil vapor probes to extract and analyze underground gases, is still in the experimental stage and has not previously been used in criminal proceedings, The Tribune reported.
Investigators confirmed the use of ground-penetrating radar, soil testing, and measurements at both the Flores property and the adjacent home. Sources told the San Luis Obispo Tribune the search was expected to last two days, though Parkinson said Friday it would continue "as long as it takes."
Smart, 19, a freshman at California Polytechnic State University in San Luis Obispo, was last seen on May 25, 1996, walking back toward her dormitory with Paul Flores after an off-campus party during Memorial Day weekend. Despite Flores' conviction, her body has never been found, and she was declared legally dead in 2002.
Earlier searches of properties belonging to Paul Flores' father, Ruben Flores, using ground-penetrating radar and cadaver dogs in 2021, also failed to locate Smart's remains.
Prosecutors alleged at trial that Smart's body had been buried under a deck at Ruben Flores' Arroyo Grande home before being moved — a claim supported by soil evidence showing human blood, though Ruben was acquitted of accessory charges.
Renewed interest in the cold case was partly credited to the true crime podcast "Your Own Backyard," hosted by journalist Chris Lambert, which launched in 2019 and was downloaded more than five million times within its first six months.
The Smart family, in a statement released Friday, expressed appreciation for law enforcement's continued efforts and said they "remain hopeful that this current search will be successful," as per the Los Angeles Times.
