The social media personality and former lawmaker known as GaaSyy was arrested upon his return to Japan on Sunday for alleged defamation threats against celebrities, an investigative source said.
The 51-year-old, whose real name is Yoshikazu Higashitani, has been living abroad but flew into Narita Airport from the United Arab Emirates on Sunday afternoon.
The International Criminal Police Organization, known as Interpol, placed GaaSyy on an international wanted list in April.
GaaSyy rose to fame as a popular YouTuber by posting videos about celebrity scandals on his channel.
He was elected to the Upper House last year as a candidate of the NHK Party, then subsequently stripped of his status as a lawmaker in March by the House of Councilors for not attending any sessions since being elected.
GaaSyy allegedly threatened to defame three people, including actor Go Ayano, in YouTube videos. He is additionally suspected of interfering with the business activities of one of the three people, the source said.
The Foreign Ministry had ordered him to return his passport after police obtained an arrest warrant against him. GaaSyy had ignored repeated requests from authorities that he return to Japan and voluntarily submit himself to questioning over the videos.
His passport expired in April after the former lawmaker submitted a report to the Japanese consulate general in the UAE saying he had lost the document.
He had been living in the United Arab Emirates since before the Upper House election in July 2022, when he won his seat.