Acting on intelligence information, soldiers found pistols, parts of an M-16 rifle, more than 100 ammunition clips and other equipment, the army said in a statement.
Separately, an Israeli security source told The Jerusalem Post the accused killers of Ben Yosef Livnat, who was fatally shot by terrorists in 2011, have been indicted in Samaria military court.
On June 19, the Israeli Security Agency (Shin Bet) said it had arrested three members of the Palestinian police involved in the attack. Livnat was killed and five Israelis wounded when shots were fired at them near Joseph's Tomb in Nablus.
The three officers were arrested by Palestinian police following the incident but on their release were arrested by the Shin Bet.
Two other Palestinian police officers also allegedly involved in the shooting have yet to be detained by the Israeli authorities, The Jerusalem Post said. One remains in a Palestinian jail and the other has gone into hiding in a Palestinian security building, the paper said.