By Katherine Mayer, M.A., CCDI
As a criminal defense investigator and mitigation specialist, I’ve watched too many strong cases crumble not because of weak evidence, but because of inadequately vetted expert witnesses. The ongoing Karen Read retrial serves as a stark reminder of why thorough expert witness vetting isn’t just important, it’s critical.
The Wake-Up Call from Boston
The Karen Read retrial has been making headlines, but what’s particularly striking from an investigative perspective is how expert witness credibility has become a focal point. Digital forensics analyst Shanon Burgess was grilled by a defense attorney over errors in his CV and LinkedIn profile, highlighting exactly the kind of credentialing issues that can devastate a case.
This isn’t an isolated incident, it’s a symptom of a systemic problem in how we approach expert witness preparation and vetting across the criminal justice system.
The Dangerous Assumption: “Someone Else Already Checked”
Here’s the uncomfortable truth: Some attorneys operate under the assumption that expert witnesses have already been properly vetted. This creates a dangerous chain of assumptions, what I call the “expert witness bystander effect.” Everyone assumes someone else has done the heavy lifting of verification, but in reality, no one has.
The prosecution assumes the expert’s previous attorney clients have thoroughly vetted them. The defense assumes the expert was recommended for good reason. The expert assumes their credentials speak for themselves. Meanwhile, the jury is making life-altering decisions based on testimony from someone whose qualifications may not withstand scrutiny.
The High Stakes of Expert Testimony
In criminal defense, particularly in mitigation cases, expert witnesses often become the entire cornerstone of your argument. They’re not just supporting players, they’re frequently the primary vehicle through which jurors understand complex evidence, psychological factors, or technical details that can mean the difference between conviction and acquittal, between life and death.
When that expert crumbles under cross-examination because they’ve overstated their qualifications, misrepresented their experience, or can’t handle the pressure of aggressive questioning, your entire case can collapse in real time.
The Comprehensive Vetting Protocol Every Defense Team Needs
1. Credential Verification: Go Beyond the CV
Don’t just accept the expert’s resume at face value. Verify every degree, certification, and professional membership listed. Contact universities directly. Check licensing boards. Cross-reference multiple versions of their CV to identify inconsistencies, just like what happened in the Read case.
2. Testimony Review: Study Their Track Record
Every expert who testifies leaves a paper trail. Get transcripts from their previous testimony, particularly in cases where they were aggressively cross-examined. You need to understand not just what they’ll say, but how they’ll hold up when challenged.
3. Equal Vetting Standards for All Experts
Here’s where some defense teams make a critical error: they vet their own experts and don’t allocate any resources to researching and vetting the prosecution’s witnesses. This practice needs to change. You should be spending at least as much time, if not more, investigating the state’s experts.
4. The Pressure Test: Mock Cross-Examination
Schedule extensive interview sessions that simulate hostile cross-examination. Don’t just review their opinions, challenge them. Test their composure, their ability to explain complex concepts simply, and their reaction to having their credentials questioned.
This isn’t about being adversarial with your own expert—it’s about preparing them for what they’ll face and identifying potential weaknesses before they become courtroom disasters.
Key Questions to Answer:
- How do they respond to aggressive cross-examination?
- Have they changed their opinions between cases?
- Are they consistent in their methodology?
- How do they handle challenges to their credentials?
- What objections have been raised to their testimony?
The Mitigation Factor: The Weight Experts Carry
In death penalty cases, the stakes become even higher. Often, an expert witness, such as a psychologist, psychiatrist, or social worker, carries the entire weight of explaining why your client’s life should be spared or why their circumstances warrant leniency. When that expert fails to connect with the jury or falls apart under cross-examination, you don’t just lose a witness, you lose your client’s future.
This is why mitigation specialists must be particularly rigorous in selecting and preparing experts. The jury needs to not just hear from your expert, but trust them, relate to them, and find them credible enough to base a life-or-death decision on their testimony.
The Cost of Cutting Corners
The temptation to skip thorough vetting is understandable. Time is limited, budgets are tight, and experts come with impressive credentials and recommendations. But the cost of inadequate vetting far exceeds the investment in doing it right.
Consider what happens when an expert’s credibility is destroyed in front of a jury: your entire theory of the case may collapse, the jury loses trust in your judgment, other witnesses’ credibility becomes suspect by association, settlement negotiations become more difficult, and appeal opportunities may be limited.
The Bottom Line: Trust, But Verify Everything
The Karen Read retrial is showing us in real time what happens when expert witness preparation falls short. Digital forensics experts faced challenges from basic credentialing issues, methodology questions that arose during testimony, and credibility became a central issue in the courtroom—these are preventable problems.
As criminal defense professionals, we owe it to our clients to assume nothing and verify everything. The expert witness who seems perfect on paper may have significant weaknesses that only emerge under scrutiny. The prosecution’s expert, who appears unassailable, may have a history of questionable testimony in similar cases.
Your client’s freedom, their future, and sometimes their life depend on the strength of the expert testimony presented on their behalf. Don’t let inadequate vetting be the weak link that brings down an otherwise strong defense.
The time to thoroughly vet your experts isn’t after they’ve been embarrassed in court—it’s months before trial, when you still have time to find better witnesses, strengthen weak ones, or adjust your strategy entirely.
In criminal defense, there are no second chances once the jury has spoken. Make sure your expert witnesses are ready for the fight of their professional lives, because that’s exactly what cross-examination will be.
The opinions expressed in this article are based on professional experience in criminal defense investigation and mitigation. Every case is unique, and specific vetting procedures should be tailored to individual circumstances and jurisdictional requirements.
