However, no charges were filed and the Briton, Iyaz Ali, will instead be deported in coming days, police said.
The statement said Ali was arrested on May 10. He told interrogators he was a member of Islamic Relief Worldwide, a British organization suspected of supporting Hamas and of transferring funds to various Hamas institutions, police said.
Israel, the United States and the European Union mark Hamas as a terrorist organization, the AP reports.
A large collection of anti-Semitic pictures were found on Ali's personal computer, including images of swastikas, senior Nazi officials and pictures of Al Qaida chiefs Osama bin Laden and Abu Musab al-Zarkawi, police said.
There are several versions of the recent assassination of the most prominent Iranian nuclear scientist and high-ranking officer of the Islamic Revolutionary Guard Corps, Mohsen Fakhrizadeh