Spanish police arrested a Saudi citizen, an Egyptian and a Moroccan over possible links to suspects in the March 11 rail bombings, the country's interior minister said Friday.
The three were arrested in Madrid on Thursday and Friday. They were being held in solitary confinement on the capital's outskirts and will probably be brought to court in the next few days, a National Court official said.
"The Moroccan was arrested because he had disappeared since March 11, the day of the attacks," Interior Minister Angel Acebes (search) told a news conference. "He was known to have ties with one of those arrested for carrying out the bombings.
"We'll see to what degree he knew the detained and what his possible role," the minister added.
Acebes said the Saudi and Egyptian were arrested for similar reasons.
"Police knew they had links with some of those believed responsible for the attacks," he said. "The arrests were made precisely to investigate what type of relation and what hypothetical role they had, or in what way they collaborated."
Their names were not immediately available.
Acebes said he expected more arrests of people who may have had a role in the attacks, links with those responsible or ties with radical Islam.
Earlier, the investigative magistrate handling the case, Judge Juan del Olmo, freed six suspects arrested over the past week. The judge ruled there was insufficient evidence to link them to the attacks, which killed 191 people and injured 1,800 others.
Eighteen people have been charged — six with mass murder and the rest with belonging to or collaborating with a terrorist organization. Fourteen are Moroccan. The others are two Indians, one Syrian and one Spaniard.
The charges do not amount to a formal indictment and do not necessarily mean the accused will stand trial.
Earlier this week, Acebes said the bombings were carried out by an autonomous cell that financed the plot by selling hashish and the designer drug Ecstasy (search).
He said most of the culprits are in custody or were killed when seven suspected terrorists blew themselves up April 3 as police moved in to arrest them.
The on-the-ground coordinator is still believed to be Tunisian real estate agent Serhane Ben Abdelmajid Fakhet, who died in the suicide blast.
But officials are examining the possibility that someone with a deeper grounding in radical Islam and perhaps terrorist training in Afghanistan or elsewhere was the overall leader of the attacks.
Investigators are pursuing leads in Britain, Germany, France, Belgium, Tunisia and Morocco.
The Interior Ministry said it was looking for a Bosnian named Sanel Sjekirica. Sjekirica said he would turn himself in when he returns from vacation in Sweden this weekend.
Sjekirica told The Associated Press he had nothing to do with the attacks. But he said he once shared an apartment with the Tunisian.