Kristin Smart murder trial: Defense argues soil stain evidence, court breaks for emotional jury

Editor's note: The People v. Flores murder trial is covered each day by Mustang News. Follow @CPMustangNews on Twitter and Instagram for more updates. Read previous articles about the trial here.

Thursday's proceedings consisted of testimony from Cindy Arrington, an archeologist who performed a search of Ruben Flores’ home at 710 White Ct. on March 21, 2021.

Prosecutor Christopher Peuvrelle asked Arrington to describe her expertise and experience in the field of archaeology. Noting her bachelor's and master's degrees as well as her experience working in sites over her 30-year-long career, Peuvrelle asked the court to designate Arrington as an expert in her field, which Judge Jennifer O’Keefe granted.

Arrington said that she had been trained in how to excavate a site when looking for human remains.

"One of the first things that appears is a stain," Arrington said. "When a body is buried in the ground… the liquids spread out horizontally and vertically and they leave a stain around the skeletal remains."

Arrington went on to explain the concept of stratigraphy, which refers to the natural process in which soils are laid down across the surface of the earth. She described "beautiful straight lines" that appear in the soil when it hasn't been disturbed over time, and went on to say that, when soil has been dug out and put back, those lines are very clearly disturbed.

During the search, law enforcement officials from the SLO Sheriff's Department suggested places for Arrington and her partner, Philip Hanes, who testified on Wednesday, to use Ground Penetrating Radar (GPR) technology to look for anomalies in the soil.

Police were looking for Smart's body, which the prosecution believes was buried under Ruben Flores’ deck and removed at some point.

The archaeologists marked eleven grids throughout the property, and Hanes said on Wednesday that they found four anomalies amongst the grids. He said he "recommended excavation of all four anomalies to be safe [to law enforcement]" but that one of the anomalies, the one on Grid One, seemed the most "promising."

Grid One was underneath the deck of the home, the same place where two human remains detection dogs exhibited a change in behavior consistent with being in their target scent (of human remains) that same day.

On Wednesday, Hanes said that the anomaly on Grid One "was a surface anomaly to depth." This indicated the presence of a disturbance through the surface layers, potentially indicating that someone had dug through the surface to where the anomaly was.

Arrington echoed this statement on Thursday, talking specifically about the lack of stratigraphy in the soil on Grid One.

"It tells us that a hole had been dug there previously," Arrington said. "That soil had been taken out and put back in."

Arrington told Peuvrelle that the soil stains were "consistent" with other human decomposition she’d seen before this case.

During opening statements in July, Ruben Flores’ attorney, Harold Mesick, told the jury that Paul and Ruben Flores would not have been able to bury a body under the deck of the house because there was no room for them to stand. During Arrington's testimony, Peuvrelle established that officers were initially able to excavate the area without removing the deck.

On Thursday, Peuvrelle showed a photo to the jury of the soil in Grid One, which revealed an irregular pattern in the soil in the shape of a ring. Arrington indicated that the pattern was outlining where fluids had leaked out into the soil at some point.

Peuvrelle asked Arrington what conclusions she could draw from the staining. She said it showed "fluid had leaked, likely from decomposition."

"We have an irregular pattern where the soil is darker than the soil within it and out of it," Arrington said. This fluid has leaked into the soil slowly over time — not quickly, or the lines would be thicker."

At this point, one of Paul Flores’ jurors began sobbing loudly in the courtroom. Judge Jennifer O’Keefe called for a lunch break 20 minutes earlier than scheduled, and proceedings were put on pause until 2 p.m., 30 minutes after they were supposed to resume.

"This has been a long trial, it has been a hard trial, and sometimes things are emotional," O’Keefe said when jurors came back after lunch. "It is not unusual for that to happen."

Peuvrelle continued asking Arrington about the stain, which she said appeared around 2 feet underground and went "a little further than 4 feet." Peuvrelle showed Arrington another photo of the soil and asked her to describe it again.

"Once the staining occurred, the soil had been disturbed again," Arrington said.

Paul Flores’ attorney, Robert Sanger, moved to strike this answer for "lack of foundation." O’Keefe overruled the objection, and Arrington continued.

"Those observations are consistent with a hole being dug, something put in there that leaks… fluids, and it being dug out."

Arrington also testified that the police found no bones during the excavation, which is not typical if a body had been placed underground. She said, however, that if the body was wrapped in a plastic tarp, fluid could’ve leaked out of it without leaving any trace of bones.

Sanger questioned this theory during his cross-examination, telling Arrington that she didn't find any evidence of a tarp or semi permeable membrane. Sanger said Arrington came up with the theory while talking to Detective Clint Cole on the phone a few days after the search, and referred to it as "brainstorming."

"So it's speculation on your part that maybe there could’ve been a tarp," he said.

"It's not speculation sir, it's experience," Arrington replied.

Later in his cross examination, Sanger said that Arrington would have found fibers in the soil if a tarp had been placed there, but she clarified that if someone had taken out a body in a tarp "after a short amount of time, there would be no evidence of a tarp because it wouldn't have started to decompose."

Arrington confirmed that she had no experience working specifically with bodies wrapped in tarps, although she maintained that the theory was possible.

Sanger continued questioning Arrington about her conversation with Detective Cole, where Sanger said that she told Cole that the staining could have been caused by roots, although Arrington said on Thursday that she remembered using the term "organic material."

During that same conversation, Arrington suggested to Cole that the body may have been buried a little further up under the deck, which she thought would explain the leakage at the excavation on Grid One. That area was inaccessible, however, and law officials removed part of Ruben Flores’ deck about a month later so that Hanes could use GPR technology to check for anomalies.

Sanger established that they never found any evidence of human decomposition in that second location.

Sanger established that Arrington doesn't know what the stains in the soil are that they found under Grid One for a fact, which she agreed with.

Sanger then pointed out one of the house's concrete walls, which went underground next to the area on Grid One. He argued that the disturbance in the soil could have been caused by a bulldozer used to put the wall underground, but Arrington said that the marks she saw in the soil were made by hand.

"We did not notice any mechanical marks," she said, clarifying that it's very easy to tell whether disturbances in soil are made by a machine or "by hand," such as with a shovel.

Arrington also said that she and Hanes found "no staining in any of the other excavations," only on Grid One.

Sanger ended his first round of cross examination by arguing that a decomposing body would have caused a substantial odor in that area of the property, although Arrington said that "the term ‘substantial odor’ is subjective," and clarified that there are many environmental factors that could affect the strength of the smell.

After Sanger asked a couple more questions, Arrington said that "a decomposing body in a shallow grave would give a strong odor."

Ruben Flores’ attorney, Harold Mesick, told Arrington that the soil stain could have been caused by a variety of things, including plant material and diesel fuel.

"One [reason] would be a decomposing body," she added.

Mesick also said that the lack of stratigraphy in the soil could have been the result of glacier runoff or a flood, although Arrington said that was "not probable… based on the geography."

Mesick then said that Smart's body would have contained about 9 gallons of fluid, and argued that "there's no staining to support 9 gallons of bodily fluid."

Arrington agreed, but added that that would only be true if her body wasn't wrapped in a semi-permeable membrane, such as a tarp.

"I just am having trouble," Mesick said. "You’re drawing all your conclusions to support the prosecution's theory."

Peuvrelle intercepted this with an objection, which O’Keefe sustained.

Arrington agreed with Mesick when he said that the staining could have an explanation other than a decomposing body being placed in the soil.

Arrington later told Peuvrelle that decomposition stains are a good indicator of a burial site, because "as a body decomposes, the fluids leak from the body. And so you would not have a burial without a decomposition stain."

Sanger clarified that, although fluid stains are a good indicator of a burial, stains can appear in soil without there being a burial. Arrington agreed.