There’s something amazing about the rapid progress made in DNA testing since it first began in 1985. The DNA fingerprinting method first used in criminal investigations yielded astounding results in the area of paternity tests but due to problems with reproducibility and the technical problem of only being able to test samples of DNA polymers fell out of use in criminal investigations. A DNA testing method using PCR (Polymerase Chain Reaction) amplification started attracting attention instead. In Japan, the DNA testing method MCT118 (D1S80) came into use in criminal investigations in 1989, with in 1992 the"Guideline for DNA Testing" then being set.

The Ashikaga case, which became famous for its retrial and acquittal, was perpetrated in May, 1990. The National Research Institute of Police Science released its DNA test results in December, 1991, and newspapers widely reported that an arrest had been made based on cutting-edge DNA testing. After the first trial and appeal resulted in a life sentence, a DNA test on hair from Mr. S., then in prison, was entrusted to me by his defense. Careful testing resulted in the DNA differing from that of the perpetrator. Did they arrest the wrong person? Was the police DNA test incorrect? In any event, it was a serious result. I therefore made an exact written report of the test, which the defense submitted in September of 1997. However, regardless of the report having been submitted to the Supreme Court during the appeal the life sentence was upheld, with the document not even being mentioned. A long retrial then ensued (during which the statute of limitations expired). Based on a re-test of the DNA for the retrial a completely innocent verdict was released in March 2010.

If the DNA was re-tested when the report on the test results was submitted to the court, the court’s stance on getting to the bottom of things would at least have been worthy of respect. That thought and the notion that there was no scientific basis for denying the request for a retrial made me despair.

The multiplex STR (Short Tandem Repeat) method currently used in criminal investigations typically tests sex chromosomes and 15 loci, normally making determination possible at the level of only being one in 10 to the power of 20. The Ashikaga case arrest was based on an experimental, rather inaccurate DNA test, but innocence proved with an accurate, state-of-the-art test. Using a DNA test of appropriate reproducibility can help corner a criminal while also reliably excluding anyone not involved in the crime.

Last July 30 the prosecutors’ request for a DNA test at the second hearing of the retrial of the Fukawa case (at the Mito District Court, Tsuchiura Branch) was denied. The Fukawa case involves a murder that was committed in 1967, in which two men were sentenced to life imprisonment, but released on parole after 29 years in prison while petitioning for a retrial. The following points are rather suspect: (1) The victim’s property was insensibly stored over a period of 43 years (with no consideration whatsoever for DNA testing). (2) The fact that"the defendants were interrogated with the items in their presence" meant the possibility that their saliva may have gotten mixed in. (3) It’s suspicious that the prosecutors would regard the DNA test as infallible, and thus request the test. I made a comment in a newspaper that the judge deserves praise for having considered the above points, and then denying the DNA test.

Consideration of what has happened over the long period spanned by the Ashikaga case in terms of changes in how DNA testing is evaluated produces a number of lessons about when and in what way cutting-edge technology should be put to practical use. The following considerations in ensuring scientific testing are important. (1) Is how the sample was collected or stored a problem? (2) Is the testing method appropriate? (3) Have the results been adequately evaluated? Furthermore, (4) is there any assurance of a re-test? No one doubts the importance of DNA testing in criminal investigations in Japan; however, some of the cases I have been consulted on were notable in that when doubt arose re-tests were no longer possible. Or cases in which there should have been enough sample material but"It got all used," or,"Went missing."

Honesty and discretion is needed in expert witnesses using cutting-edge technology, especially now, when the consciences of scientists are being called into question. With this in mind we published"Q&A Mite Wakaru DNA-gata Kantei (Understanding DNA Testing through Questions and Answers)" (published by Gendaijinbunsha), aiming at lawyers and jurists, but it comes with an easy-to-understand DVD, allowing citizens chosen as lay judges to also refer to it.

After the first decision in the Ashikaga case (in 1993), I keenly felt the true spirit of journalism at work in the magazine AERA, which published the article,"The Collapse of the DNA Myth". However, following the Supreme Court’s decision, there should have been just as strict a reappraisal of what has been written in praise of DNA testing. I feel strongly that there is also a need for earnest scrutiny of the influence the media, including newspapers, can have on criminal trials involving advanced testing.

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