Supreme Court & PCR Controversy

On December 22 last year, the Japanese Supreme Court revoked a high court’s decision which overturned the lower court’s decision to retry a murder case from 1966. As the ruling admits the the high court decision was fraught with problems going so far as to suggest data manipulation, without evidence, by the petitioner’s expert witness.

Asahi Shimbun, “EDITORIAL: Swift retrial only way to ensure Hakamada receives justice” (January 3, 2021()

Five justices of the chamber apparently spent hours wondering how to judge a legal/scientific issue involving DNA testing hotly debated among opposing experts. In the end, 3 out of 5 justices upheld the high court’s conclusion finding the petitioner’s expert testimony as unreliable. Interestingly, the reason the majority cite 19 times for the finding is the possible “contamination” of the specimen. As the term was never used in Supreme Court’s published criminal decisions, one would wonder where this sudden sensitivity came from. The answer: COVID-19.

In the course of COVID-19, the Japanese society hotly debated if the PCR testing would be reliable because of “contamination” in the testing process. Even the health authorities cautioned that there could be “false positives” arising from specimen contamination and other causes, presumably to justify the lack of adequate testing capacity. As a result of the dubious debate, the ill-defined “contamination” risk now has a place in the law precedents for years to come.