One of the alleged masterminds of the 2002 Bali bombings has arrived in Indonesia after being extradited from Pakistan, officials in Jakarta say.
Umar Patek, who was arrested in January in the same part of Pakistan where Osama Bin Laden was killed, is expected to be charged with murder.
Mr Patek is accused of helping to make the bombs that killed 202 people, many of them foreigners, on the island.
He is said to be the only major suspect who has not been killed or arrested.
Mr Patek has been linked with the militant group Jemaah Islamiah (JI), which was blamed for the attacks.
He is believed to have worked closely with the attack's organiser, Dulmatin, who was killed by Indonesian police last year.
Mr Patek was also reportedly involved in at least three other attacks in Indonesia - and said to have links with militant groups in the southern Philippines and al-Qaeda members in other parts of Asia.
The BBC's Karishma Vaswani in Jakarta says the extradition is being seen as a significant coup for the anti-terror agencies in the country.
Security experts believe that he will be able to reveal links between terror cells in Pakistan, Indonesia and the Philippines, our correspondent says.
Officials said he would be not be charged with terrorism because the laws were enacted after the Bali bombing. He is instead expected to be charged with murder, which carries the death penalty.
"He cannot be prosecuted under the anti-terrorism law because it cannot be imposed retroactively," said Ansyaad Mbai, head of the Anti-Terrorism Agency.
"[But] he is a murderer and bombmaker, which also breaches the criminal code. It's now up to the investigators."
The suspect was arrested earlier this year in the Pakistani town of Abbottabad, where al-Qaeda leader Osama Bin Laden was later killed by US forces.
The US said it appeared to be a coincidence that he was in the same area.
But Mr Mbai disputed that, saying that several other militants were arrested in the same area, suggesting a link between international jihadi organisations.
"Patek was very valuable for the US. He helped lead authorities to bin Laden," he told the Associated Press news agency.
JI, which has been linked to al-Qaeda, has a long track record of bomb attacks in Indonesia.
The group's goal is the establishment of an Islamic state in Indonesia and in other parts of South East Asia.