According to Israeli radio, the intelligence agency has removed a gag order on the case of Yousef Nasrallah, a 20-year-old Palestinian from the central Israeli city of Qalansawe, who was arrested last December after returning to Israel from Jordan.
Nasrallah confessed under interrogation that he had travelled to Syria via Jordan last April but had been arrested by the Syrian authorities hours after entering the country, the Shin Bet was quoted as saying.
He said he was interrogated by Syrian regime officials and asked to pass on information about Israeli security facilities.
In Syria, Nasrallah said he was subjected to severe torture during his interrogation and returned to Israel after being released in a critical state of heath, the Shin Bet said.
"The phenomenon of Palestinians traveling to Syria is most dangerous, as the Syrian arena is filled with activity by elements hostile to the state of Israel, particularly global jihad operatives," the Shin Bet said in a statement.
On Monday, an indictment was filed against Nasrallah in Petah Tikvah's Magistrate Court in central Israel.
Last November, Israeli prosecution authorities indicted Hamza Magasma,a Palestinian from the northern town of Yafa al-Naseriyye, after accusing him of having trained in Syria with ISIL.