Earlier, Katju, a former Superme Court judge, had said that the cartoonist did nothing illegal.
Trivedi was arrested on Saturday on sedition and other charges following a complaint that he had put up banners mocking the Constitution during the Anna Hazare rally held in 2011 in Mumbai and had also uploaded obscene content on his website.
He was produced in a Mumbai court on Sunday which sent him to police custody till September 16.
He was sent to jail on Monday after a local court remanded him to two-week judicial custody as police submitted that their investigations in the case were over and his custodial interrogation was not needed.
Katju also lamented that there was "no freedom for press" in Bihar and claimed that though there was no physical assault on journalists, those who write against the state government were dismissed or transferred to remote area.
"There is no freedom of press in Bihar. Although that was my tentative view, I have set up a fact finding committee, which is likely to submit its report by the end of this month," he said.