Who Is Acting as the Judge? The Judge or the Forensic Expert?

From the perspective of a grassroots fact-finding judge, what are a judge's views and expectations regarding forensic science? Frankly speaking, I think the problem lies in the fact that "judges do not understand, but judges need to make judgments and conclusions."

I once mentioned in a lecture to high school civics teachers that scientific evidence is actually quite popular among judges, because credible scientific evidence greatly reduces the brain cells lost by judges during the process of "weighing the case circumstances" and "cross-examining evidence." However, scientific evidence is not a road sign that can directly tell you where the truth lies. Evidence requires interpretation, and most evidence involves subjective elements—such as the reading of polygraph tests (which some experts consider pseudo-evidence), the reading of fingerprint characteristics, or the reading of shoe print matches. Therefore, scientific evidence may contain errors.

If I were to describe judges' general stance on forensic evidence, I would use the phrase "accepting it wholesale." The reason is simple: judges do not understand, but judges need to make judgments. However, I often feel that in certain cases, it is not I who am acting as the judge, but the forensic personnel. So, how can we prevent forensic personnel from playing the role of the judge?

I believe no judge would dare to state with absolute certainty that Taiwan's criminal procedure system will never wrongfully convict an innocent person. Therefore, whether judges act as substantive judges themselves or allow forensic personnel to do so, the shared risk is erroneous judgment.

Currently in Taiwan, almost all units with criminal forensics capabilities are administrative agencies, or rather, investigative agencies. Personally, I think this is a problem. Theoretically, prosecutors represent the state in prosecuting criminal suspects, but regarding the facts of the prosecution, the prosecutor representing the state and the defendant may have disputes over part or all of the facts. If such disputes can be clarified by experts using forensic methods, the court will commission experts to conduct evaluations. However, judges later discovered that almost the vast majority of criminal forensics experts are in the Criminal Investigation Bureau, the Investigation Bureau, and the Military Police Command. While this is normal because they need forensic units to find criminals, during a trial it becomes "state public servants using forensics to prove that the defendant prosecuted by the state is a bad person." Judges need another group of experts—whether in academic units or private companies—who can examine those forensic results at trial or provide defense counsel with professionally standard cross-examination suggestions.

Furthermore, relying on forensic personnel within executive departments has another problem, which is subordination to superiors. I once heard that a forensic pathologist who actually performed an autopsy had a different opinion from the pathologist authorized to sign and issue the official document, and as a result, the opinion in the autopsy report was not that of the pathologist who signed the expert's oath, but that of his superior. If this is true, I consider it extremely terrible. I have always believed that forensics is a science and forensic personnel are scientists, but this situation clearly does not meet scientific standards.

Many years ago, the collegiate panel I belonged to tried a well-known case. The defendants were initially called the "Tu Father and Son Case." Later, the father passed away from terminal cancer before the conviction became final, leaving only the two brothers, so social activists and academics named it the "Tu Brothers Case." This case is classic because it is the only case in Taiwan where the court of first instance delivered an acquittal, but all subsequent retrials in the second instance delivered death sentences. Moreover, both the first and second instance judgments cited the expert opinion of Weng Ching-hui, a very famous expert in Taiwan. However, the same expert came to court to testify twice, and his expert opinions—subject to cross-examination—were respectively cited by the acquittal judgment and the death penalty judgment. Because all forensic evidence came from mainland China, and mainland China does not accept Taiwanese forensic personnel, prosecutors, or judges going there to verify their forensic results, the prosecutor came up with a method during the first instance trial: asking a Taiwanese expert to study the mainland forensic report beforehand, and then having this expert come to court to submit a report "evaluating whether the mainland forensic report complies with forensic routines and whether it is credible." Mr. Weng Ching-hui should have been Taiwan's top expert at the time, so naturally he was invited. When he came to testify the first time, he fully cooperated with the prosecution's performance, giving the court mostly affirmative professional opinions while cautiously expressing certain worries and "dissatisfaction." This portion of his testimony formed the core of the death penalty judgment. Later, after the collegiate panel perceived the worries and dissatisfaction just mentioned, they once again exercised their authority to invite him to testify a second time. Through questioning, he emphasized that forensic science must have qualified laboratories and professional personnel who comply with occupational ethics (scientific ethics) for the evaluation results to be credible. He also mentioned that Taiwan had experienced a past era where "forensic departments were (requested) to cooperate with investigative departments," and he did not know whether mainland China had experienced the same situation or had progressed beyond it. The three judges of the district court collegiate panel were presumably influenced by him to make a judgment that strict proof could not be established, and they quoted parts of Weng Ching-hui's worries and dissatisfaction in the judgment.

If the professional evaluation presented by an expert in court ends up being cited respectively as the grounds for acquittal and conviction, wouldn't you all find that terrifying? And even worse, the judgment convicting the defendant was handed down by a higher court that had never personally heard Mr. Weng Ching-hui's expert opinion!

Ever since that case, I knew that forensic opinions are subjective and prone to error.

During my third year as a probationary judge, a close friend from my cohort spent all day overthinking things. She worried that during the urine testing process for drug use, name tags might be mismatched, urine samples contaminated, or framed by others, resulting in a flawed report that would wrongfully incriminate a defendant. Another close friend and I laughed at her every day, calling her crazy and saying that with such worries, she would never be able to handle cases. Yet, she actually quit criminal law. Over a dozen years later, I realized that I was the fool and her worries were entirely possible...

Here, I list cases I personally experienced or cases with concrete facts, and these cases highlight the risks of forensic error that current judges are unable or struggling to rule out:

1. Using the wrong reagent for testing—The Chiang Kuo-ch'ing Case. According to the reasoning of Ruling No. 001 (Year 100 of the Republic) of the Northern Division Military Court of the Ministry of National Defense: the "anti-human hemoglobin serum immunoprecipitation test," used to determine human blood, was instead used to confirm semen stains. (However, an investigation officer from the Bureau of Investigation later checked the archives and stated that no such situation existed.)
2. Using a truth serum (antianxiety medication) for psychiatric evaluation—The Cheng Chieh Case. Lorazepam Ativan clinically produces immediate hypnotic/sedative effects upon injection. According to the evaluating physician's statement in court, this method was used to "break down the defendant's psychological defense." (According to the evaluating physician's statements in court and relevant literature, information obtained through drug-assisted interviews cannot be accepted by the court for procedural and substantive adjudication. He also admitted that the statements obtained through drug-assisted interviews are not necessarily completely truthful.)
3. Are polygraphs "investigative science," "forensic science," or pseudo-science?—The Huang Chih-cheng Robbery-Homicide Case (prior to the sixth retrial, all second-instance judgments sentenced him to death, with one reason being that polygraphs are credible and the defendant exhibited deceptive responses; the seventh and eighth retrials changed the judgments to acquittal, with one reason being: polygraph evidence still cannot match blood DNA comparisons or seal evaluations, where accuracy reaches near-absolute objectivity and can be adopted as primary evidence).
4. Forensic results of "not ruling out the possibility"—The Ch'en Lung-ch'i Case:
   • Conviction judgment: Criminal Investigation Bureau forensic report: "Does not rule out being mixed with Ch'en Lung-ch'i's DNA or someone sharing the same paternal lineage... The acid phosphatase test is a preliminary test for semen, not a confirmatory test. The microscopic examination is a confirmatory test for semen; finding sperm cells confirms semen, and when sperm cells are not found under microscopic examination, the prostate-specific antigen test can be used as an auxiliary test to determine if it is a semen stain. Sample 53003819 collected from the victim Yi's underwear showed no sperm cells under microscopic examination, but the prostate-specific antigen test was positive. Based on the above, it is judged that the stain is extremely likely to be semen."
   • Acquittal judgment: After re-examination by expert witnesses Liu OO, Nien OO, and Wu OO from the Forensic Science Office of the Criminal Investigation Bureau, Ministry of the Interior, it was found that the gene type combinations of co-defendants A and B both revealed Ch'en Lung-ch'i's genotype. Therefore, the "mixed type" referred to in the victim's underwear sample could be mixed with the DNA of defendant Ch'en Lung-ch'i and co-defendants A and B, or it could simply be mixed with the DNA of co-defendants A and B. In other words, the forensic result of "not ruling out being mixed with defendant Ch'en Lung-ch'i's DNA" could mean it was mixed with his DNA, or it could mean it was not mixed with his DNA at all.
5. There was once a case where the defendant denied that a modified firearm had lethal capability. The court asked the Criminal Investigation Bureau to conduct a test firing. As a result, the Criminal Investigation Bureau's expert stated under cross-examination in court that because there were too many firearms awaiting examination and out of fear of a barrel explosion risk, they did not perform a test-firing inspection (kinetic energy testing method) but only performed an appearance inspection. The court held that such an evaluation could not prove it could fire bullets and thus acquitted the defendant, but the judgment was ultimately remanded by the Supreme Court. The Supreme Court's reasoning was that test-firing inspections are not strictly necessary to confirm lethal capability, and the Criminal Investigation Bureau's expert even proudly stated that 12 divisions of the Supreme Court supported their decision not to test-fire. I believe this is not science; this is an appeal to the authority and support of the Supreme Court. Furthermore, why did the Criminal Investigation Bureau perform a test fire on the gun modified by Tang Shou-i in the 319 Shooting Incident when it also carried a barrel explosion risk?

When I searched and read about the Chiang Kuo-ch'ing and Ch'en Lung-ch'i cases mentioned above, I truly felt terrified inside. Because I had no idea what reagent should be used to test semen stains, nor why combining the bodily fluids of persons B and C would produce person A's DNA type. In other words, judges lack even the ability to "spot problems," so how could they possibly have the ability to judge whether forensic results are correct? I suppose only scientists on par with the experts have that ability. But I don't even know where to find such scientists; all I know are the experts inside the aforementioned Criminal Investigation Bureau, Investigation Bureau, and Military Police Command, alongside university professors who may not necessarily agree to assist or be willing to come to court for cross-examination. When errors occur involving experts from the agencies I know, what should judges do? What should defendants do? What should defense counsel do?

The only solution I can think of is "testability." Only through this can forensic experts firmly establish themselves in the position of scientists, or at least move toward it.

I believe the following changes must be made:

1. Real-name system for forensic opinions. If a superior disagrees with a forensic opinion, that superior should sign their name. Do not let subordinate experts go to court to state their superiors' opinions and be subjected to cross-examination.
2. Assist and encourage private or academic institutions to cultivate forensic talents—that is, to build a mechanism capable of reviewing the forensic results of the Criminal Investigation Bureau, Investigation Bureau, and Military Police Command.
3. Establish standard operating procedures that comply with international standards, including processes for evidence collection, testing, and report writing (for example: how many feature points must fingerprint identification match to be considered a match? What kind of waves in polygraph testing are considered meaningful? How can a modified firearm be confirmed to possess lethal capability?). At the very least, allow judges to formally observe whether scientific requirements are met.

Regarding sciences outside of trial and legal studies, judges are complete laymen. At most, they can only rely on limited logical reasoning for a very superficial evaluation. I used to wonder how the Supreme Court's "N requirements" regarding the admissibility of polygraph evidence came about. Supreme Court judges are not experts; how on earth could they write those requirements that "look so professionally learned"? I suspect they must have consulted polygraph experts, and those polygraph experts provided foreign standards which the Supreme Court then adopted. The problem is that whoever told the Supreme Court judges about these standards must be an expert who strongly promotes the credibility of polygraphs (otherwise they would become irrelevant). The judges then accepted them, widely plagiarized them, and whipped them out whenever defense counsel or defendants challenged the admissibility of polygraph results, ruling them admissible.

If judges do not change, they will simply continue to let forensic personnel act as substantive judges, while judges continue to act as their rubber stamps!

※ The original text of this article is a speech manuscript, published after authorization by the author and editing and revision by the JRF editorial team