Raja Petra is already in jail under a law that allows detention without trial
A prominent anti-government blogger has gone on trial in Malaysia on charges of sedition.
Raja Petra Kamaruddin, who is already in jail after being detained under the Internal Security Act, faces charges dating back to an April blog posting.
In the blog, he allegedly implied high-level involvement in a murder case.
His supporters say he is being punished twice, as part of government efforts to use the judiciary to punish its political opponents.
Raja Petra published the country's best-known political blog, Malaysia Today.
In the April posting, he published an article entitled "Let's Send the Altantuya Murderers to Hell".
This allegedly suggested that involvement in the 2006 murder of 28-year-old Mongolian woman Altantuya Shaariibuu went as high as the office of Deputy Prime Minister Najib Razak.
Mr Najib has consistently denied any involvement.
Ms Shaariibuu had worked as a translator on several government trips.
Prosecutors in the case say two policemen killed her and blew up her body with explosives.
They claim that think-tank director Abdul Razak Baginda, a close associate of Mr Najib, collaborated in the murder because the woman was demanding money after he ended an affair.
The three men are on trial for the murder.
The Associated Press reported that Raja Petra looked frail when he was brought in handcuffs in a police van for the trial.
"They are penalising him twice... It's double jeopardy. But his spirits are up," said Raja Petra's wife, Marina, at a district court, AP reported.
Several dozen supporters greeted Raja Petra at the Kamunting Jail in central Malaysia, wearing T-shirts with slogans such as "I am with RPK", "Free RPK", and "No to ISA".
Raja Petra was arrested on 12 September under the Internal Security Act (ISA) as part of a government clampdown on opposition voices.
An opposition member of parliament and a journalist also arrested at the same time were soon released.
Mr Najib is widely expected to take over as prime minister when incumbent Abdullah Badawi agrees on a transition date.
Mr Abdullah has lost widespread support following the ruling party's poor showing in elections in March.