Indonesian prosecutors have formally charged the man alleged to have planned last year's bomb attacks on the resort island of Bali.
Samudra is thought to have learnt to make bombs in Afghanistan
Imam Samudra, thought to be a senior member of the militant Islamic group Jemaah Islamiah, has been charged with "planning" the Bali attacks, which killed more than 200 people, mostly foreign tourists.
If convicted, he could face the death penalty, prosecution spokesman Mohammed Salim told the Associated Press news agency.
Imam Samudra is one of 29 people detained in connection with the Bali bombings.
Last week, a car mechanic called Amrozi became the first Bali suspect to go on trial, accused of buying the chemicals to make the bombs and the van used to transport them.
A team of prosecutors handed over a
43-page indictment against Imam Samudra on Wednesday morning, along with several items of evidence including a laptop computer and a detonator allegedly used in one
of the bombings.
Court official Nengah Sarwa said the trial could start on 28 May or 2 June.
Imam Samudra was arrested last November as he tried to flee the Indonesian island of Java on a passenger ferry.
Police accuse him of being the brains behind the Bali attacks.
He is said to have chosen the target and led planning meetings - even staying in the resort for four days after the attack to monitor how the police investigation began.
Police say he is an engineer with a university education, and that he learned how to make bombs in Afghanistan.
Asked if he was sorry for the Bali victims during a Australian television interview on Monday, Imam Samudra is reported to have replied: "Ask the Australians if they are sorry they killed Iraqis."
As well as the Bali attacks, he has also been charged in connection with a series of church bombings on Christmas Eve 2000, as well as the robbery of a gold shop, the proceeds of which - according to the authorities - were used to finance the Bali attacks.
Jemaah Islamiah, a regional militant Islamic group wants to set up a pan-South East Asian Muslim state.
Jemaah Islamiah has been blamed for the Bali attacks, as well as the 2000 church bombings and a foiled plot to blow up Western embassies in Singapore.
The group's alleged leader, Abu Bakar Ba'asyir, is currently
on trial in Jakarta in connection with the church attacks.
He has not been charged in the Bali