Post-conviction litigation rarely captures public attention, even when it follows a highly publicised criminal trial. Yet it is often during habeas corpus proceedings that courts take their most searching look at how a case was actually tried. These proceedings do not relitigate guilt or innocence. Instead, they ask a narrower but profound question: was the defendant afforded the effective assistance of counsel guaranteed by the Constitution?
That question is now central to a habeas petition filed by actor Danny Masterson, who in 2023 was convicted in Los Angeles of raping two women at his Hollywood Hills home in 2003 and sentenced to 30 years to life in state prison. The petition, filed with California’s 2nd District Court of Appeal, alleges that his trial lawyer failed to call key witnesses and did not introduce evidence that could have altered the outcome of the case.
For expert witnesses, the filing provides a timely case study in how omissions at trial—particularly the absence of expert testimony—can become focal points in post-conviction review.
Background of the Case
Masterson, best known for his role on the television series That ’70s Show, was charged in 2020 with three counts of rape involving three women. All of the alleged assaults occurred in 2003, a period during which Masterson was at the height of his acting career.
His first trial in 2022 ended in a mistrial after jurors were unable to reach a unanimous verdict. One count was split 8-4 for conviction, another 7-5, and the third resulted in a 10-2 vote for acquittal. Prosecutors elected to retry the case on two counts, declining to pursue the third.
At the retrial in 2023, a new jury convicted Masterson on both remaining counts. He was subsequently sentenced to 30 years to life under California’s sentencing scheme for forcible rape. Throughout both trials, Masterson maintained his innocence.
The habeas petition now before the appellate court focuses not on witness credibility or jury findings, but on the performance of his trial counsel during the retrial.
The Habeas Claim: Ineffective Assistance of Counsel
In his petition, Masterson argues that his attorney, Philip Cohen, provided constitutionally deficient representation. Specifically, the filing asserts that Cohen failed to call witnesses and present evidence that could have challenged the prosecution’s narrative and supported the defense.
Under longstanding Supreme Court precedent, courts evaluating such claims apply the two-part test articulated in Strickland v. Washington. The petitioner must show both deficient performance and resulting prejudice. It is a demanding standard, particularly in cases where defense attorneys can point to strategic reasoning.
This is where expert witnesses frequently become critical. Courts often rely on expert testimony to assess whether counsel’s actions were within the range of reasonable professional judgment at the time of trial.
Why Expert Witnesses Matter in Habeas Proceedings
Unlike direct appeals, habeas petitions permit courts to examine evidence outside the original trial record. That includes expert opinions evaluating trial strategy, investigative thoroughness, and prevailing professional norms.
Experts in these proceedings are not asked to determine guilt or innocence. Instead, they may be asked to address questions such as:
• Whether certain types of expert testimony were commonly used in similar cases
• Whether such testimony was reasonably available to trial counsel
• Whether failing to present it deviated from accepted professional practice
In sexual assault cases, these questions take on heightened importance because juror interpretation often turns on behavioral context rather than physical evidence.
Sexual Assault Trials and the Use of Experts
The Masterson case, like many sexual assault prosecutions, involved allegations reported years after the alleged events and lacked contemporaneous forensic evidence. Such cases often rely heavily on testimony, memory, and credibility assessments.
Expert witnesses are commonly used in these contexts to explain:
• Trauma-related memory patterns
• Delayed reporting behavior
• Inconsistencies that may arise from psychological stress
• Institutional or social pressures affecting witnesses
When expert testimony of this kind is absent, defense teams may later argue that jurors were left without the tools needed to evaluate the evidence fairly.
Strategic Decisions Versus Deficient Performance
Courts are careful not to equate every unfavorable outcome with attorney incompetence. Trial lawyers are granted wide latitude in making strategic decisions, including whether to call expert witnesses.
However, that deference is not unlimited. If trial counsel failed to investigate the availability of expert testimony, misunderstood its admissibility, or neglected to consider its potential impact, a court may conclude that the decision was not truly strategic.
Expert witnesses retained during habeas review often play a central role in making this distinction. Their opinions may help courts determine whether counsel’s choices reflected informed judgment or fell outside professional norms.
Evaluating Prejudice: The Most Difficult Element
Even if deficient performance is established, habeas relief requires a showing of prejudice. The petitioner must demonstrate a reasonable probability that the outcome would have been different had the omitted evidence been presented.
Here again, expert witnesses may be called upon to explain:
• How expert testimony could have reframed juror understanding
• Whether it could have countered prosecution themes
• Whether it might have influenced deliberations in a close case
The hung jury in Masterson’s first trial adds factual context to this analysis. Defense attorneys may argue that the initial lack of unanimity demonstrates how additional evidence or expert testimony could have tipped the balance in the retrial.
The Limits of Expert Testimony
Courts remain cautious about expert overreach. Experts cannot speculate about juror decision-making or opine directly on witness credibility. Their role is to educate the court about professional standards and evidentiary context.
For expert witnesses, credibility in habeas proceedings depends on restraint, transparency, and grounding opinions in contemporaneous practice rather than hindsight.
Practical Lessons for Expert Witnesses
The Masterson petition offers several lessons for experts who work in criminal litigation:
• Early consultation matters. Experts engaged during trial preparation can shape strategy and preserve issues for review.
• Documentation is critical. Consultation notes and reports may later be scrutinized.
• Admissibility must guide opinions. Expert testimony is only valuable if it would likely have been allowed at trial.
• Neutral analysis strengthens credibility. Courts value experts who acknowledge limitations as well as strengths.
Expert Witnesses During the Retrial
1. Claire Headley — Scientology Practices Expert (Prosecution)
• Role: Testified about teachings and practices of the Church of Scientology relevant to the case.
• Purpose: Headley, a former senior member of Scientology’s Sea Org who later became a critic of the church, explained doctrines and cultural practices that prosecutors argued affected the accusers’ reporting behavior—such as discouragement against reporting alleged wrongdoing to outside authorities.
• Context: Her testimony was allowed in the retrial after being excluded in the first trial.
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2. Dr. Barbra Ziv, M.D. — Effects of Alcohol/Drugs and Memory (Prosecution)
• Role: Provided expert analysis on how substances like alcohol and drugs can affect cognition and memory.
• Purpose: Ziv replaced the prosecution’s initial expert from the first trial and offered context on how alleged intoxication could influence recall and behavior.
• Focus: Her testimony was permitted to discuss general effects on the brain and memory—not to directly opine on the accusers’ credibility, but to help jurors understand how intoxication might impact their recollections.
• Context: Included as an admitted expert because the judge found it would assist jurors given the nature of the allegations.
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3. LAPD Criminalist — Toxicology & Drug Effects (Prosecution)
• Role: An expert from the Los Angeles Police Department specializing in drug analysis.
• Purpose: Offered general testimony about how “date rape drugs” and other substances can be administered and behave physiologically.
• Context: Used to support the prosecution’s framing of the accusers’ experiences of intoxication, even though the prosecution did not formally allege drugs were administered by the defendant.
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4. Hugh Martin Whitt — Scientology Practices Expert (Defense)
• Role: Named on the defense witness list as an expert on Scientology.
• Purpose: Intended to offer an alternative perspective on Scientology teachings and organizational culture. Whitt is a high-level Scientologist and the estranged stepfather of Claire Headley.
• Context: The defense listed this expert to counter Headley’s anticipated testimony, though reporting indicates he ultimately was not called to testify.
By Eddie Price
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