How expert witnesses explain evidence and maintain ethics

Most people have seen an episode of some kind of crime procedural television show that depicts a court case with a witness on the stand, answering questions posed dramatically from either side as a jury watches on.

“All the garbage criminal forensic shows that are on TV,” Victor Vigluicci said. “Those shows are not realistic.”

Vigluicci is the Portage County Prosecutor with over a decade of experience in the office and said the biggest hurdle to making a jury understand a case can be those television shows.

“We have to get away from what they see on TV because that’s often over-simplified and inaccurate,” Vigluicci said.

How do courts go about making sure that a jury understands the evidence presented in a case?

According to Timothy Smith, an emeritus professor at Kent State and a criminal defense attorney, creating a pool of informed jurors begins in the selection process.

“Each side gets an opportunity to question prospective jurors,” Smith said. “They ask questions about who you are, what you are, what you do.”

In the selection process, prospective jurors fill out a questionnaire which both the prosecution and the defense can then see. The questions are tailored to try and identify any biases that the jurors might hold that could impact their ability to make an impartial decision at the end of a trial.

“In the process of picking a jury, you’re also trying to subtly indicate to the jury what the case is about,” Smith said. “And find people who might be, at least potentially, sympathetic to your point of view.”

After the selection process, it’s up to the prosecution to prove their case.

“The prosecution has the burden of proof,” he said. “They’ve gotta prove a case beyond a reasonable doubt.”

Because it’s on the prosecution’s shoulders to prove that a crime was committed by the defendant, it’s most often the prosecution who wants to make things like financial and forensic evidence easily understandable to a jury.

This is where expert witnesses come in.

Dr. Anthony Tosi is a professor of Forensic Anthropology at Kent State, but before joining the university, he worked out of the Office of the Chief Medical Examiner in New York where he is one of a handful of people throughout the country who specialize in “touch DNA.”

Touch DNA is a form of forensic DNA testing that can pull samples off of things a suspect or victim may have touched — such as a weapon, an item of clothing, or a length of rope.

“It’s the case details that we have to go into,” Tosi said. “Explaining, you know, what items were examined, how they were examined, what samples were taken off of the evidence, why they were taken off of the evidence, how everything was documented.”

Echoing Vigluicci’s concerns, Tosi said that television and movies that convey forensics can work against them when trying to explain the evidence to a jury.

“Hardly any of them have any forensic background,” he said. “They think they might because of CSI shows… They expect all the bells and whistles that they see from Hollywood and that’s not how it operates in real time.”

Most forensic testing isn’t as definitive or as fast as these TV shows like to portray them as, Tosi said.

Expert witnesses like Tosi are typically brought in by the prosecution and work closely with them to prepare to testify in front of a jury.

These witnesses have the task of simplifying evidence for a jury to understand. In Tosi’s case, this means breaking down his scientific methods of analyzing DNA and helping a jury understand what the results mean.

“Before every case that would go to trial, we would have at least one pre-trial, if not there would be a meeting to discuss the case, the trial, how they were going to list off the questions, in what order, to kind of build the case,” Tosi said.

Tosi said that it would usually begin by building the background of his training and the laboratory’s training in order to build his credentials for the jury before getting into the specifics of the forensics and the case.

“We would work through the case and then we would work through the questions,” he said. “How to best deliver this information to the jury in a way that was understandable, succinct.”

In Portage, it falls on Vigluicci’s office to make sure witnesses are prepared for the stand.

“The scientists that we use from the Bureau of Criminal Investigation out of the Attorney General’s office are pretty well-versed in first educating the jurors as to the scientific foundations,” he said. “And then going through that very methodically with jurors.”

But how dependable is testimony from someone the prosecution is paying to speak on the stand?

“Sometimes there are other issues,” Tosi said. “Like, you can get pressure from your supervisor. You can get pressure from the NYPD or the police department that’s associated with you because they want to solve the case.”

Tosi said that, during his time in the Office of the Chief Medical Examiner, he came up against his supervisors when he didn’t feel comfortable telling they jury what he was expected to.

“It probably caused me problems because, you know, I would dig in sometimes and I wouldn’t give in to my supervisors,” he said. “But sometimes there are relatively few opportunities for promotion and the people who get promoted are the ones who generally people in the upper tiers can rely on to kind of fall in line.”

Expert witnesses are paid to take the stand by either the prosecution or the defense. This can lead to some concern they will build the narrative of that side, whether it’s accurate or not.

“There’s always the concern that the expert will go the direction that they’re being paid,” Smith said. “There’s always the fear that the expert basically will say whatever you want them to say.”

Smith said the best way he’s found, as an expert witness on libel law himself, to avoid this is to build one’s credentials with both the defense and the prosecution to appear unbiased to the jury. Tosi, however, said he avoided being swayed by sticking to his convictions and trusting the science.

“You have to just be true to yourself, I think,” Tosi said. “You know, you have to just dig in and, you know, maintain your integrity.”