They are really getting very desperate.
After Tomoko's murder Japanese tourists almost quit coming to Sukkothai. It was a critical tourist issue, besides a murder, and got more attention than most. Still nothing or no one was ever really linked to the murder, (there were rumors, of which we cannot mention here) Tomoko's parents, who seem to have some push in Japan have kept demanding answers, and the Japanese government keeps the pressure on.
In 2019, Justice minister Somsak Thepsutin told the Japanese police & embassy officials (& press) that the suspected murderer had died in 2010, likely poisoned. His name was not given. However that theory is gone, discarded, tossed, with no explanation as to why. Now a mystery Frenchmen, the holder of "crucial information" is put in the crosshairs of the Thai dragnet.
Back in 2019, the DNA sample had markers of an East Asian man. Nothing said about that DNA now, instead a mystery Frenchmen has surfaced, 18 years after the crime, he may break the case.
Or not.