Lab used in Kristin Smart trial may have incorrectly analyzed DNA in hundreds of cases

The lab that tested DNA in the Kristin Smart case may have incorrectly analyzed DNA in up to 580 cases across California, court documents show — with the error forcing a mistrial in a Sonoma County murder case.

Now parties involved in the Kristin Smart case are considering whether the lab’s reported error may impact Paul Flores’ 2022 murder conviction.

On Tuesday, The Press Democrat reported that the Serological Research Institute had notified Sonoma County prosecutors about the analysis issue, prompting a mistrial in the case against Daniel Carrillo for the 2016 murder of 18-year-old Kirk Kimberly.

The DNA evidence in that case was analyzed incorrectly in 2018, according to The Press Democrat.

Court records show the nonprofit Richmond-based lab, known as SERI, said the issue was “human error” caused by a laboratory employee who incorrectly input information that affected the outcome of an instrument used to detect DNA.

The mistake occurred in January 2017 but wasn’t discovered until January 2022, court documents said. The problem was corrected on Feb. 2, 2022. Only one type of DNA analysis instrument was affected by the error, court records said.

“There was no defect in the software. The instrument did exactly what it was told to do by incorrectly programmed software,” SERI executive director and quality assurance manager Gary Harmor said in court records May 14.

Harmor said about 580 cases were identified for review after discovering the error in 2022.

“Due to the scale of the corrective action, corrections are still ongoing at the time of this memo,” he said, adding that the majority of cases can be reinterpreted with the original test.

Lab used in Kristin Smart trial may have incorrectly analyzed DNA in hundreds of cases by Kaytlyn Leslie on Scribd

DNA analyzed by the same lab was used in the trial against Paul and Ruben Flores for the murder of Cal Poly freshman Kristin Smart.

Paul Flores was convicted and sentenced to 25 years to life, but his father Ruben Flores was acquitted.

Harold Mesick, Paul Flores’ attorney, told The Tribune on Wednesday the issue may impact Flores’ appeal.

San Luis Obispo County Assistant District Attorney Eric Dobroth meanwhile said the agency “will convene to determine if there is any potential application in the Smart case or any other cases in San Luis Obispo County.”

He noted that cases prosecuted by the office do not depend on DNA alone, saying that evidence presented by the prosecution hinges on a “constellation” of evidence to prove a defendant committed a crime.

When reached for comment by The Tribune to ask if there was a way to confirm whether the Smart case was affected by the error, a SERI employee laughed, said “no” and hung up the phone.

Lab tested DNA for Kristin Smart case in 2021

In 2022, SERI senior forensic DNA analyst Angela Butler testified during the Smart trial that the lab tested for both the presence of human blood and DNA. The tests were done in 2021, according to court records and her court testimony.

She said tests showed human blood was present in soil samples taken from underneath Ruben Flores’ deck, but that DNA was not found on those samples, adding that degradation, time and conditions could deteriorate DNA presence.

According to Butler, the lab also analyzed a piece of plywood from a cargo van that belonged to Mike McConville, boyfriend of Paul Flores’ mother, Susan Flores, and a canvas mattress cover presumably from Paul Flores’ 1996 dorm room.

One “very weak” positive result for a presumptive human blood protein test was found on the plywood sample, and because the sample was so small Butler opted to perform a DNA test rather than risk deteriorating the sample more by a confirmatory human blood test, she said.

The DNA test ruled out Smart and both Flores men, but was a match for McConville, Butler said.

She analyzed nine areas of the mattress pad for “touch DNA,” or DNA that would be found when someone touches something, such as skin cells or perspiration. A small brown stain, around the size of a dime, yielded a presumptive positive test for human blood, Butler said.

Results from that DNA test on the mattress pad sample showed a “DNA mixture,” meaning there was more than one person’s DNA found, Butler testified. She said she decided to test for DNA rather than perform a second blood test for the same reason she opted for a DNA test on the plywood sample.

She said she used a “probabilistic genotyping” software, which helps analyze DNA, especially degraded and mixed samples. The software found three possible DNA contributors to the small brown stain, she said, and neither Smart nor Paul Flores could be included or excluded as a match.

At least one contributor was a male, she said.

The other eight areas did not yield any positive results, Butler said. Two areas had too many contributors to analyze, she said, and six excluded both Smart and Flores.

Defense attorneys Robert Sanger and Harold Mesick both attempted to discredit Butler during the trial, focusing on whether the blood tests were validated and whether the DNA test meant anything significant for the case.

According to an analysis by The Tribune, the county paid SERI $36,088 for its work in the Smart case.

DNA not focus of juror decision-making process

It is unclear what would happen if Smart’s case was affected by the DNA testing issue at this time.

According to jurors who spoke with The Tribune in April 2023, DNA evidence played a smaller role in their decision to convict Paul Flores.

Nine out of 12 jurors were ready to convict Flores on the first day, but three were on the fence, they said.

According to one of the jurors who were unsure, the three on the fence had to make sure there was enough circumstantial evidence to outweigh not having a physical body.

According to the jurors, the most important pieces of evidence were the testimonies of the two women who said Flores raped them following Smart’s disappearance and the soil evidence found at Ruben Flores’ home.

The jurors said the women who testified that Flores raped them established a pattern and made them believe Flores attempted to rape or raped Smart before her death.

The soil evidence found at Ruben Flores’ home was the positive human blood tests — not DNA — and was not affected by this SERI testing issue.