Police sources say a former Japanese lawmaker arrested for allegedly intimidating celebrities has told investigators that he didn't think his actions were illegal.

GaaSyy, whose real name is Higashitani Yoshikazu, was arrested on Sunday after returning from the United Arab Emirates.

The former YouTube creator is accused of repeatedly threatening an actor, a businessperson, and a designer in videos posted online between February and August last year.

The suspect reportedly admitted to posting the clips but told investigators that he didn't think that what he said in the videos was unlawful.

Investigative sources say GaaSyy began uploading videos after acquaintances told him he would be able to make money by posting celebrity gossip.

He was elected to the Upper House last year, but was expelled for failing to appear at Diet sessions.