Cal Poly San Luis Obispo's News Source

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.

The trial for Paul and Ruben Flores continued Monday with testimony from a forensic DNA analyst who confirmed the presence of human blood in soil samples from the Flores’ property. 

After a week-long break, Monday’s hearing began with testimony from Angela Butler, a senior forensic DNA analyst and Laboratory Supervisor at Seri Lab assigned to the Kristin Smart case.

Previous witness testimony indicates that detectives with the San Luis Obispo Sheriff’s Department sent evidence to Seri Lab in 2019, 2020, 2021 and 2022, some of which they collected from Ruben Flores’ home in Arroyo Grande, at 710 White Ct.

The prosecution believes that Paul and Ruben Flores buried Smart’s body there at some point.

Butler testified that she received two soil samples from the Sheriff’s Office in March of 2021, one labeled “Upper Soil Sample” and another labeled “Deeper Soil Sample,” both presumably from Ruben Flores’ property. Butler said she sorted through the samples to find pieces that look “unusual.”

Butler described finding fibers of “various colors” in the samples, which she noted were “very unusual.” 

After extracting liquid from the soil samples, she performed a confirmatory test for blood.

The test for the “Deeper Soil Sample” confirmed three positive results, two weak positive results and one negative result using a HemDirect test. 

The HemDirect test, as Butler explained, detects the hemoglobin present in human, primate and ferret blood. 

On Aug. 29, Edward Chadwell, the contractor in charge of building Ruben Flores’ home in Arroyo Grande, testified that there were no human, primate or ferret bodies on the property when he built it in 1991. Other witness testimony throughout the trial has echoed this statement, with no witnesses testifying to the presence of primate or ferret bodies in 710 White Ct.

Prosecutor Christopher Peuvrelle asked Butler about what the results of the HemDirect test meant.

“What is the significance of these results to you, as a criminalist?” Peuvrelle asked. 

Paul Flores’ attorney, Robert Sanger, objected to this question. Judge Jennifer O’Keefe overruled the objection.

“As far as the conclusions I can draw, I have confirmed the presence of human blood on these samples,” Butler said. 

The “Upper Soil Sample” did not give any positive results.

Butler then attempted to extract DNA from both of the samples, but said that “there was no DNA present in any of the samples,” adding that she could not conclusively say why.

Peuvrelle asked her if the reason why she didn’t find any DNA could be due to the samples being degraded over time, which Butler agreed was a possibility. 

Butler said that “you may not get any results” when testing for DNA when it isn’t stored properly over time.

In April 2021, about a month after receiving the original samples, Butler received another evidence package from the SLO Sheriff’s Department. 

She said she found multiple colored fibers in these samples as well, including red, black, white, blue and some clear fibers. 

According to previous witness testimony, Smart was wearing red shoes, black vinyl shorts and a gray top the night she went missing.

Some of the samples from April also tested positive for human blood with the HemDirect test, totaling 13 positive results in combination with the ones from March. Butler said that all of the results were double-checked by another person at Seri Lab.

Sanger objected multiple times to testimony from Butler about the person who confirmed the tests, arguing that it was “hearsay.” Judge O’Keefe overruled the objections.

Butler said that she did not find or recover any DNA from this second batch of samples either, explaining that it was for the same reason as before. 

Butler also received a piece of plywood for testing from the SLO Sheriff’s Department, which came from Mike McConville’s pickup truck. 

McConville is Susan Flores’ boyfriend. Previous witness testimony indicates that, in 2019, he parked his truck in Ruben Flores’ home in Arroyo Grande overnight. The prosecution believes that he may have been helping the family transfer Smart’s body that day.

Butler said that she found a very small area in the plywood, less than the size of a dime, that “gave an indication for the presumptive test for blood” when she examined it.

Because she didn’t want to risk wasting the sample for the confirmatory blood test, Butler instead made the decision to swab it for DNA.

The DNA results excluded Kristin Smart, Paul Flores and Ruben Flores from the sample, indicating that the DNA was not theirs. McConville, however, was included as a contributor to the DNA in the plywood.

The last piece of evidence that Butler testified about on Monday was a canvas mattress pad, which presumably belonged to Paul Flores when he lived in Room 128 of Santa Lucia Hall in 1996. 

Butler examined it in 2019, where she sampled nine areas looking for DNA. A small brownish stain, labeled 11A, gave a weak positive result for the presumptive test for blood. None of the other eight areas gave any positive results.

Like the plywood, Butler did not want to waste the 11A sample doing a confirmatory test for blood, so she tested it for DNA.

Peuvrelle asked Butler what determinations she could make from the DNA test.

“Well, it was a very low-level, degraded sample,” Butler said. “And the results show that Kristin Smart and Paul Flores could neither be included nor excluded as contributors to the DNA results obtained from this sample.”

She later added that the DNA mixture was interpreted as originating from three contributors with at least one male, although Butler said there wasn’t one singular main, stronger contributor for the mixture.

She said that both Kristin Smart and Paul Flores were excluded from all of the areas that were tested on the mattress except for 11A. 

However, she later added that two of the samples, 11B and 11E, suggested that more than four people had contributed to the DNA mixture. She explained that the amount of contributors made it “too complex” for the technology to interpret. 

During his cross examination, Sanger established that an unbalanced pH level can offset the HemDirect test. He asked Butler if she checked the pH levels of the samples before testing them for human blood.

“It’s not necessary, but no,” Butler said. 

Butler said it is documented in literature both from the manufacturer and research that checking the pH levels of a sample is not a necessary step of testing for human blood.

Later, Sanger established that the HemDirect test has never been validated for use in soil, citing an email from Christian Stadler from SERATEC, the lab that created the test. 

Sanger added that there has been no validation studies to prove that the test works in soil samples, which Butler agreed with.

Butler’s testimony was set to resume Tuesday morning.

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