A forensic expert was on the stand once again during the Kristin Smart murder trial Thursday.
Dr. Elizabeth Johnson was questioned by Paul Flores' attorney, Robert Sanger. Johnson talked about the test used to determine whether any blood was in the soil beneath the deck of Ruben's Arroyo Grande home.
The prosecution’s theory is that Kristin Smart's body was buried there and later moved.
Earlier in the trial, another forensic specialist testified that the soil tested positive for blood but Dr. Johnson told jurors those tests were likely false positives as blood would break down in soil after a short amount of time.
She also said the test used can be affected by pH levels and the soil pH was never tested.
On cross examination, San Luis Obispo County Deputy District Attorney Christopher Peuvrelle asked how long it's been since Dr. Johnson worked in a lab setting, She said 2003 was the last time she worked full time.
Peuvrelle pointed out that was before the iPhone was invented resulting quickly in an objection from Sanger.
Peuvrelle also pointed out that Dr. Johnson has worked almost exclusively for defense attorneys for the past 20 years.
Court is expected to resume Monday.
The prosecution has rested its case. Once the defense is done calling witnesses, both sides will present closing arguments before the juries for Paul and Ruben began deliberating.
If convicted, Paul, charged with the murder of Kristin Smart, faces a sentence of 25 years to life. His father, Ruben, faces a maximum sentence of three years behind bars. He’s charged as an accessory, accused of helping cover up the crime.
Kristin was a 19-year-old freshman from Cal Poly when she disappeared after an off-campus party in May 1996.
Her body has never been found.
Nicolás Viñuela contributed to this report