Spain's supreme court has acquitted four of 21 people convicted of involvement in the Madrid train bombings of 2004.
It also upheld a lower court's decision to acquit one of the alleged masterminds of the al-Qaeda-inspired attacks, Rabei Ousmane Sayed Ahmed, known as 'Mohammed the Egyptian'.
The early morning bombings on four packed commuter trains on 11 March 2004 were the deadliest terrorist attacks in the West after the 11 September 2001 strikes against the US.
On 31 October last, Spain's anti-terrorist court convicted 21 people of involvement.
But following an appeal, the Supreme Court has acquitted Basel Ghalyoun and Mohamed Almallah Dabas, who were each sentenced to 12 years in prison for belonging to a terrorist group.
It also acquitted Abdelilah El Fadual El Akil, who was sentenced to nine years for collaborating with a terrorist group, and Raul Gonzalez Pena, who had received five years for supplying explosives.
