The prosecution issued an indictment against Eyal Yaffe on Sunday for illegal ownership of weapons and ammo.
The suspicions against Yaffe emerged late last month after footage surfaced of him at an anti-government protest in Jerusalem.
In it, he can be seen closing in behind a female Border Police officer. She later filed a police complaint.
When Yaffe was apprehended, police searched his home and found guns, ammunition, grenades, and military equipment, the Sunday indictment reads.
The prosecution requested that his detention be extended until the end of the proceedings, and until the end of the trial.