AUSTIN (KXAN) — Forensic science experts were called to the stand Friday in the fourth full day of testimony in the trial for Mark Alan Norwood.
Norwood, 62, is charged with capital murder in the 1988 beating death of Debra Masters Baker. He has entered a formal not guilty plea and proclaims his innocence.
Lee Hernandez, a former crime scene specialist with the Austin Police Department, took the stand to testify about Norwood’s DNA collection that was carried out on Sept. 21, 2011.
Follow Hernandez’s testimony, a number of representatives from the laboratory that performed analysis of Norwood’s DNA sample took the stand, explaining their results that point to Norwood as the suspected murderer.
“We could not eliminate Mark Alan Norwood or any of his maternal relatives,” said Shelley Johnson, with Mitotyping Technologies and Fairfax Identity Laboratories.
The prosecution pointing to what they say is the crux in this case.
“Technology and science had the opportunity to really catch up with this crime,” said Travis Co. Assistant District Attorney Katie Sweeten. “We’ve been able to use technology and science to go back and look at an old case through a different lens, and it’s just a hugely important investigative tool.”
Meanwhile, Norwood’s defense team spent the day Friday denying the credibility of DNA forensic science.
“If it was a slam dunk, we wouldn’t have 1,400 cases in our county that have to be re-tested,” said Brad Urrutia.
A hair analyst with the Department for Public Safety lab in Austin testified Thursday about three questioned hairs found at the 1988 crime scene. Melissa Valadez completed visual examinations of the hairs when she retrieved them in 2005. At that time, she found that all three hairs appeared to be from a Caucasian individual, they were possibly pubic hairs, and all were “visually different” from the victim’s known pubic hair sample.
Baker, 34, was beaten to death in her home in January 1988. The case went unsolved until August 2011 when prosecutors say DNA evidence found in Baker’s home was a match to evidence found in the 1986 murder of another woman, Christine Morton.
Two forensic science experts took the stand at the end of the day Wednesday to begin the DNA expert witness testimony.
“You can still look at the hair under the microscope, but you can’t say that the hair came from one particular person, to the exclusion of all others,” said Irma Rios, an expert witness from the former Department for Public Safety, or DPS Lab. Rios is currently working for the Houston Forensic Science Center.
Jurors have heard extensive testimony from forensic scientists who gave them a basic lesson about DNA and a brief explanation about its compilation process.
General DNA Analysis Procedure:
- Extract DNA
- Quant DNA
- Amplify DNA
- Analyze DNA
“DNA testing took hold in the late 1990’s with STR Testing,” Theresa Francis testified Thursday. Francis is a former forensic scientist for Austin’s DPS Lab. Francis is now employed with the Virginia Department of Forensic Science.
Francis also gave a history of the types of DNA testing and its progression. It included the types of DNA testing, which are comprised of:
- ABO blood typing (before DNA)
- STR testing