Deputy CSD Commander Pol Col Prasobchok Prommoon announced at a news conference that Veerasak Iampongsa, 39, was apprehended for the premeditated murder nearly 20 years earlier while he was on a Bangkok-Trang bus when it reached the southern province of Nakhon Si Thammarat's Tung Song district.
Mr Veerasak allegedly murdered Awaji Megumi, then 33, in Japan and escaped to Thailand where he had been in hiding for 19 years and 7 months.
Japanese authorities cooperated with Thai authorities for the arrest.
The suspect confessed he knew the victim in early 1993 through his Japanese girlfriend, whom he had met in Bangkok and who later invited him to work at a bar in Japan.
The cause of the murder was alleged to be that they had argued about money and that the victim, with gambling problems, had looked down on Mr Veerasak, calling him a prostitute and spitting in his face.
The suspect stabbed the victim once and strangled her before taking her valuables.
Col Prasobchok said the case, whose statute of limitations will expire on March 14, was the first criminal case that Japanese authorities had sought cooperation through the Attorney General’s Office and was successful.
Without an extradition treaty, the Japanese government asked the Thai authorities to carry on with punishment in accord with Thai law, so the suspect will be tried in Thailand's Criminal Court.