The revelation was made by a man accused of taking part in the attacks at the holiday resort as he gave evidence on Wednesday at an Indonesian court on Wednesday.
Ali Imron, who has previously admitted to being involved in the attacks, laughed out loud at one stage in court.
He was testifying in the trial of his elder brother Mukhlas, whom Indonesian prosecutors accuse of being the mastermind.
Imron said the attacks took six days to prepare. One of the attackers, he revealed, wore an explosives-laden vest in Paddy’s Bar on the Kuta Beach nightclub strip.
Outside the club a minivan packed with explosives was parked across the street by the Sari Club.
“We used cell-phone detonators. In the Paddy’s we used the detonator, it was in the vest of Iqbal or Issa. For the Sari Club bomb, it was inside the car and detonated using cell phone buttons. It went as scripted,” said Imron, who is yet to be brought on trial himself.
The prosecution has said a man called Isa wore the vest, while Iqbal parked the minivan.
Confused, tense and happy
When prosecutors asked Imron how he felt about the bombings, Mukhlas, sitting in the defendant’s chair, started laughing out loud.
“Confused. Really confused. I couldn’t eat. I felt tense . . . happy, tense, happy,” said Imron. “Honestly, I had doubts whether this was really jihad or not.”
Jakarta has alleged Mukhlas, 43, is the operations chief of Jemaah Islamiah, a southeast Asian militant Muslim network it has blamed for the attacks and which has been linked to Al-Qaeda.
Mukhlas, who faces the death sentence if convicted, retracted last month all statements made to the police, saying that he was tortured and forced to say he was part of the operation. The police have denied this.
A third brother, Amrozi, has admitted his role in the attacks during his trial and said he was proud that they killed white people. Prosecutors have demanded that he be sentenced to death.