Jordan 'bomber' had brothers killed in Iraq

They said the woman, Sajida Mubarak Atrous al-Rishawi, 35, had provided few leads apart from her apparent motivation and the investigation was now focused on whether the bombers had accomplices in Jordan.

A security source said Samer al-Rishawi, a right-hand man of Iraq's most wanted man Abu Musab al-Zarqawi, was among the three brothers killed by US forces battling insurgents in the west of the country.

Samer was a cell leader for Zarqawi, the Jordanian-born Al-Qaeda frontman in Iraq, for the volatile Al-Anbar province, the source said.