Theo Van Gogh released a fictional film in August about the mistreatment of Muslim women. In the film, women were shown naked with texts from the Quran 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 Quran in Arabic, though police would not confirm this. According to NRC Handelsblad, the note called for an Islamic holy war, or jihad.
Van Gogh's killing, which came two years after the murder of populist anti-immigration politician Pim Fortuyn in 2002, stirred outrage and fears that Dutch people will no longer feel free to speak their minds.
The arrests were made in the 24 hours since Theo van Gogh was slain while cycling down an Amsterdam street Tuesday - believed to be the first Islamic terrorist attack in the Netherlands.
