AMSTERDAM, Netherlands (AP) -- Dutch prosecutors said police have arrested eight more suspected Islamic radicals as part of ongoing investigations into the brutal killing of outspoken Dutch filmmaker Theo van Gogh.
The arrests were made in the 24 hours following Van Gogh's slaying while he was cycling down an Amsterdam street, prosecution spokeswoman Dop Kruimel said Wednesday. They are in addition to the arrest of the alleged killer, a 26-year-old Amsterdam resident of Moroccan origin.
Six of the detainees are of Moroccan ancestry, one is Algerian and the last has dual Spanish-Moroccan nationality, Kruimel told The Associated Press.
Kruimel said the suspects, whose identities were not released, were detained and released during an October 2003 investigation into a potential terrorist threat.
"They were previously known to us," Kruimel said. "As of now only one suspect is being held for Van Gogh's murder, but the investigation will determine if others may have been connected."
The Dutch have reacted with outrage to the killing of the celebrity filmmaker who criticized Islam, testing the nation's famed tolerance and straining already tense relations with the large Muslim immigrant population.
Mainstream Dutch Muslim groups condemned Tuesday's killing, which some experts are calling the first act of Islamic terrorism in the Netherlands. A number of mosques were closed Tuesday night for fear of vandalism and political figures were given additional police protection.
The respected NRC Handelsblad reported that conservative politician Ayan Hirsi Ali, who wrote the script for Van Gogh's latest provocative movie criticizing the treatment of women under Islam, received a death threat in an e-mail Wednesday that read "You're next."
The Justice Ministry said the suspect in the murder of Theo van Gogh -- a distant relative of the famous painter Van Gogh -- is a Muslim radical associated with Islamic fundamentalists on a terrorist watch list.(Full story)
Authorities did not release his name, but Dutch media identified him as Mohammed B.
Members of parliament called for an emergency debate on why the culprit -- who police say had a record of violent crime -- had not been stopped.
"Is this a murder, or is this a terrorist attack?" said Jozias van Aartsen, leader of the conservative VVD party. "The facts must come out very, very quickly."
Van Gogh released a fictional film in August about the mistreatment of Muslim women who were shown naked with texts from the Koran scrawled on their bodies.
Police and eyewitnesses said the attacker shot Van Gogh, stabbed him, cut his throat with one knife, and pinned a note to his chest with another.
The note is said to have contained texts from the Koran in Arabic, though police would not confirm this. According to NRC Handelsblad, the note called for an Islamic Holy war, or Jihad.
The killing of brash social commentator Van Gogh after the murder of populist anti-immigration politician Pim Fortuyn in 2002, drew outrage and fears that people will no longer dare to speak freely.
Immigration minister Rita Verdonk told 20,000 Dutch who flocked to Amsterdam's central square for a noisy wake Tuesday night "we won't take this."
Verdonk called an emergency meeting with leaders of Muslim groups to discuss how to avoid confrontations. Prime Minister Jan Peter Balkenende appealed for calm.
Interior Minister Johan Remkes confirmed that the suspect in Van Gogh's murder was known to have associated with a group of 150 radicals who are watched day and night by the Dutch secret service for fear they may commit a terrorist act.
The Netherlands has arrested more than 40 terrorism suspects since September 11, 2001, including many accused of providing logistical support for al-Qaida linked groups. But there has never been a terrorist attack on Dutch soil.
"At moments like this, people's prejudices come out," said Masite Halici, a young Dutch woman of Turkish ancestry who came to lay a rose where Van Gogh was killed.
"They are angry, fearful, grieving. But this is not about Muslims or non-Muslims. This is about people being able to say what they think."