The San Luis Obispo County Sheriff’s Office says since 2011, there have been more than 40 search warrants served in the Kristin Smart investigation.
Law enforcement adds there have also been physical evidence searches at more than 15 separate locations. But 25 years since her disappearance, the 19-year-old Cal Poly student's remains are still missing.
KSBY News talked to a local expert who is not involved in the case to offer some insight into the search for evidence.
San Luis Obispo-based forensic scientist Larry Stewart worked for the U.S. government for over 25 years. He worked on many notable cases like the Unabomber investigation and the reinvestigation of the assassination of Dr. Martin Luther King Jr.
Now with more than 40 years of experience, in recent years, he reexamined a case in which a death row inmate convicted of murdering an elderly woman in Alabama was released from prison.
“I was able to show they had the wrong person and a lot of that had to do with soil and debris that was found at the scene,” Stewart said.
Some of the searches in the Kristin Smart case have centered around soil, too.
Ground-penetrating radar was used in the backyard of Ruben Flores’s home this March and April. Flores is the father of Paul Flores, the man arrested this April for Kristin Smart's murder.
“You would go through layer by layer looking at the sediment layers to see how they're laying down on each other and whether or not they have that layered look or if they look like they're disturbed,” Stewart said.
Stewart says, generally speaking, body parts and blood found in the soil can be tested for decades.
“In a case like a missing person, sometimes police will use something called luminol and luminol is a spray that reacts with hemoglobin and blood and using an ultraviolet light which is essentially a black light. It makes it glow,” Stewart said.
He says that shows law enforcement where they should take samples for the lab.
X-ray fluorescence spectrometers are also useful in identifying blood. The device can pull up the percentage of the inorganic composition of the sample.
“So if I was looking for remnants of a body and I was looking for blood, I would be looking for iron so you would have Fe which is the element name for iron,” Stewart said.
San Luis Obispo County Sheriff's detectives have not revealed what evidence was found during the searches at Flores's Arroyo Grande home, but investigators dug in several locations around the yard.
In a lawsuit filed this April, the Smart family alleges that Kristin's body was buried at the home on White Court and that Ruben Flores, his estranged wife, Susan, and Susan's boyfriend, Mike McConville, moved the remains in February of 2020. In criminal court, Ruben is charged with being an accessory after the fact, accused of helping his son move Kristin's remains.
A preliminary hearing for Paul and Ruben Flores is scheduled to begin on July 6 and last approximately 12 days.