Updated

Terrorists who carried out the Madrid train bombings were members of a autonomous cell who may have had ties with fundamentalists elsewhere but got their financing chiefly from drug profits, the interior minister said Wednesday.

Officials are investigating 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 March 11 attacks (search) that killed 191 people, but aren't sure such a person even exists, Interior Minister Angel Acebes (search) said.

Acebes said the person "has been called the emir," but would not give any other details.

Spain has received a letter and a video from an Al Qaeda-linked group claiming responsibility for the Madrid attacks that warned of more violence unless Spain withdraws its troops from Iraq and Afghanistan. But they believe the group was largely confined to Spain and most of its members are either in custody or dead.

The on-the-ground coordinator of the attacks is believed to be Serhane Ben Abdelmajid Fakhet (search), a 35-year-old Tunisian real estate agent who blew himself up with six other suspects on April 3 as police moved in to arrest them, Acebes told a news conference.

The interior minister's remarks came as reports emerged that the cell might have been planning to target Jewish targets in Madrid. Members of Spain's Jewish community and Spanish officials said Wednesday that police searching the apartment where the suspects killed themselves found a document that mentioned a Jewish cemetery and cultural center called La Masada in a mountain town 20 miles northwest of Madrid.

Police searched the area around Hoyo de Manzanares but found no bombs, said Fernando Esteban, the mayor of Hoyo de Manzanares.

"They told us documents were found in the ... apartment in which the Masada center was named which indicated it might be a possible target," Esteban told The Associated Press.

The Interior Ministry and officials at the National Court denied that evidence had been found which might indicate the any Jewish site might have been a target.

Acebes said the cell that staged the March 11 attacks "was local and autonomous, but its leaders have connections with other fundamentalist groups." He said investigators are pursuing leads in Britain, Germany, France, Belgium, Tunisia and Morocco.

The groups funding came chiefly from drug sales, he said. The bombers apparently obtained the dynamite from petty criminals in a coal-mining region of northern Spain who accepted drugs as payment, Acebes said.

The bombers also used proceeds from drug sales to rent an apartment, buy a car and purchase cell phones used as detonators in the bombs, which also wounded more than 1,800 people in four commuter trains, Acebes said. He gave no figure on how much money the bombers had raised with the drug sales.

Acebes repeated that the core of the cell has been neutralized through a wave of arrests and the deaths of the suspects who committed suicide. But he refused to rule out future attacks by cell members who remain at large.

"Further actions cannot be ruled out, given the fanaticism of these individuals," Acebes said.

Police are investigating whether the three bodies that remain to be identified from the apartment explosion might include someone who oversaw Fakhet's activities, Acebes said.

Eighteen people have been charged in the attacks — six with mass murder and the rest with belonging to or collaborating with a terrorist organization. Fourteen of the 18 are Moroccan.

Six other suspects arrested over the past week have yet to go before a judge.

A fugitive Bosnian suspect named by the Interior Ministry, Sanel Sjekirica, 23, said from Sweden on Wednesday that he would turn himself in to the Spanish authorities this weekend.

Sjekirica told AP he once shared an apartment with Fakhet but had nothing to do with the attacks.

"I was surprised," Sjekirica said. "Of course it is not correct."