Cleared for publication: A resident of Umm al-Fahm was arrested on suspicion of carrying out offenses that undermine Israel's national security.
Police and the Shin Bet are investigating the case in northern Israel, with an Israeli citizen at the center of the affair.
Khaled Muhammad Sliman Agbaria, 51, suspected jeopardizing national security, is already in custody.
The Nazareth Magistrate's Court on Tuesday extended his arrest by 13 days, but banned the publication of the investigation's details.
On Monday, an indictment was filed against a 22-year-old resident of Beit Safafa, who was accused of making contact with a foreign agent. The man is suspected of contacting Hamas operatives during his academic studies in Cyprus, and agreeing to collect intelligence on sites in Israel for the Muslim Brotherhood in Jerusalem.