The Superior Court of Pennsylvania granted inmate Scott Hopkins a new trial. On November 22, 2013, a Beaver County jury had convicted Hopkins of third-degree murder in the 1979 slaying of Janet Walsh. But the appellate court has now ruled that the prosecution's "topographic distribution" theory of old semen stains "shall not be admissible" at the new trial.
On September 1, 1979, Walsh's body was discovered in her Monaca, PA apartment. There was no sign of recent sexual activity, nor of any semen deposits, according to the investigating officers, autopsy pathologist, and State Police criminalist at the time. Hopkins told the police that he had a relationship with Walsh, having visited her weeks before the murder.
In 2010, a State Police serologist searched for semen stains on items from the crime scene. The state crime lab analyzed the stains she found, comparing them with Hopkins' DNA. They found his DNA on the back of Walsh's nightshirt, the bathrobe tie that bound her hands, and on a bed sheet. Hopkins was charged with the murder.
On September 27, 2012, noted forensic pathology Cyril Wecht prepared an expert report for the prosecutor, Assistant District Attorney Frank Martocci. Wecht considered the co-location of Hopkins DNA on "the back of Walsh's nightgown and on the soft white rope tied around the decedent's wrists (her arms were bound behind her back)."
Wecht opined that the "seminal fluid DNA, in these locations, placed [Hopkins] on the bed on top of the decedent's back at/around the time of her demise." He further opined that "it is extremely unlikely that [Hopkins'] seminal fluid was deposited in those locations during the two or three previous sexual encounters … 3 weeks to a month prior to the victim's death."
Hopkins' defense attorney, James Ross, objected to the unscientific basis of this opinion, citing the Pennsylvania Rule of Evidence 702 on expert witness testimony. Ross filed a motion to preclude Wecht's expert report and testimony. On November 5, 2012, Court of Common Pleas Judge Harry Knafelc agreed with Ross, finding that the results were "inadmissible."
Needing Wecht's testimony to make his case, ADA Martocci appealed the suppression order to the Superior Court of Pennsylvania. On October 4, 2013, the appellate court reversed, ruling that the "report regarding the location of seminal fluid, [and] its time of deposit ... meets Pennsylvania's liberal standard for expert testimony." A third judge dissented.
At the November 2013 trial, the forensic question was when Hopkins left his DNA in Walsh's bedroom. Wecht testified that the DNA was left at the time of the murder. Cybergenetics chief scientist Mark Perlin testified that it was equally likely that Hopkins' DNA was left weeks before the murder, during consensual sex with Walsh.
Perlin explained that the co-location coincidence might be due to transfer. Hopkin's DNA, left on Walsh's nightshirt from sexual activity weeks before, could have transferred to the rope/robe tie that bound her hands, and later to the bedsheets. The conditions were ideal for DNA transfer: abundant moisture, considerable pressure, lengthy time, and cloth materials.
Weighing in the defendant's favor was Mr. Hopkins invisible semen. "The stains are invisible on the back of the blue night shirt, the semen stains aren't visible on the cotton robe tie, and the stains are invisible on both of the bed sheets," testified Dr. Perlin at trial. It is "extremely unlikely that a trained police investigator, a trained pathologist, a trained coroner, and a trained criminologist at a crime lab would all miss four semen stains."
The Beaver County jury found Hopkins guilty. He was sentenced to 8-16 years in prison. As CBS 48 Hours news show reported in their "Janet's Secret" episode, the jury was impressed by Wecht's DNA testimony. His "topological distribution" theory that Hopkins' DNA was deposited at the time of the murder, but not before, seemed persuasive.
Appellate lawyer Adam Cogan has long been fighting Hopkins' conviction. His appeal of Hopkins' Post-Conviction Relief Act (PCRA) petition again questioned the admissibility of Wecht's opinion under Rule 702. But now he focused on paragraph 702(c) – that the "topographical distribution" methodology was not generally accepted in the scientific community (the Frye standard).
Wecht mentioned "topographical distribution" three times in his testimony at the Hopkins trial. His preceding expert reports did not contain the phrase, nor did they mention such a methodology. Reviewing the trial and PCRA record, the Superior Court of Pennsylvania found this novel methodology lacked scientific acceptance.
Indeed, the PCRA Court had found Wecht's methodology rested on "unscientific conjecture and speculation" that "every layperson uses." The Superior Court saw a contradiction: "the Commonwealth relied heavily on [this unscientific] testimony," yet argued to the jury that "science, caught up to" Hopkins. The prosecution couldn't have it both ways.
At trial, former public defender Martocci objected to established forensic science. When Perlin showed TrueAllele (software for more in-depth DNA analysis, having Pennsylvania Frye precedent) results, Martocci wrongly argued that "zero" match information meant "guilt." The ADA's sustained objections kept the jury from learning more about DNA transfer. Martocci's objections blocked Dr. Perlin from teaching the jury why scientific evidence must compare alternatives (e.g., topography vs. transfer).
The Superior Court wrote: "Without Dr. Wecht's topographical distribution testimony, the Commonwealth had no other evidence purporting to prove that the DNA deposits took place around the time of Walsh's death. In view of [Hopkins'] sexual relationship with Walsh, the jury might well have concluded that, but for Dr. Wecht's testimony, the DNA deposits occurred during one or more sexual episodes earlier in the summer. Only through his testimony was the Commonwealth able to persuade the jury that [Hopkins] was the murderer."
The Superior Court decided to "reverse the order denying PCRA relief, and remand for a new trial in which expert testimony concerning 'topographical distribution' shall not be admissible." The Beaver County District Attorney has two weeks to file an appeal.
The appellate opinion opens the door for raising new pre-trial admissibility issues in a post-conviction setting. For example, DNA mixture evidence has been misinterpreted using ineffective methods that are not generally accepted by the scientific community. Yet defense lawyers usually don't challenge the Frye admissibility of unvalidated forensic methods.
Will defense lawyers now be tarred with "ineffective assistance of counsel" for not raising Frye challenges against novel forensic science? Are new DNA avenues opening up for post-conviction relief? To avoid overturned convictions, must prosecutors somehow guarantee the admissibility of their forensic evidence, even in the absence of a pre-trial Frye challenge?
The Hopkins case raises even more questions. Did the DNA evidence prove his guilt, or did it prove his innocence? Was there a "topographical distribution" (prosecutor's theory) or a "DNA transfer" (defense view)? How does the invisible semen come into play?
For an answer to these and other forensic questions, see Perlin's presentation on "Justice denied: Mr. Hopkins invisible semen," given at the American Investigative Society of Cold Cases 2016 Annual Conference.
Republished courtesy of Cybergenetics.