The Shin Bet security service and the State Prosecutor's Office are to submit an indictment against Palestinian engineer Dirar Abu Sisi, who has been held in custody in Israel for close to 40 days.

Abu Sisi, who is believed to have information abducted Israeli soldier Gilad Shalit, disappeared from Ukraine and resurfaced in an Israeli jail last month.

Notification of the indictment was relayed Wednesday to Abu Sisi's attorney, Smadar Ben-Natan.

According to the notification, a "prosecutor's statement" will be submitted Thursday to the Petah Tikva Magistrate's Court, indicating an intention to indict a suspected criminal.

Despite details of the case being under gag order, Prime Minister Benjamin Netanyahu said Wednesday that Abu Sisi is a member of Hamas.

"He is a Hamas member, held legally in Israeli detention. He gave important information," the prime minister said, without elaborating, during an interview aired on YouTube.

Relatives of Abu Sisi, 42, deny that he is a militant. They also deny claims that he has information about Shalit.

Netanyahu's statements about Abu Sisi appears to violate the gag order on this case.

Deputy president of Petah Tikva Magistrate's Court, Judge Lia Lev On, who on March 20 removed the gag order on Abu Sisi's arrest, decided to ban the "release of any details of the investigation and arrest" until April 17.

Asked if the prime minister had violated the gag order, Netanyahu's associates said he had "checked this point with senior army and defense officials and received their go-ahead" before the interview, and had therefore not broken any order.

The Shin Bet, which is conducting Abu Sisi's interrogation, refused to comment on whether the gag order had been violated. But even if the Shin Bet concludes that Netanyahu's statement did not cause any security damage or obstruct the interrogation, neither the security service nor the prime minister are authorized to act directly against an explicit court order without first speaking to the judge who signed it. As far as is known, no such move was made.

The court is set to discuss Thursday the Shin Bet's request to extend Abu Sisi's remand until Monday, when the indictment will apparently be formally submitted. Abu Sisi has been held in custody for nearly 40 days. His family members claim he was seized in the Ukraine and taken to Israel by plane.

The former Gazan engineer, who is being held in Shikma prison in Ashkelon, met Wednesday with Ben-Natan, and denied reports published this week by the German weekly Der Spiegel suggesting he has information about Shalit.

Basing its claim on a variety of sources, Der Spiegel implied that the main motivation behind Abu Sisi's arrest is the possibility that he is in possession of information about Shalit's whereabouts. Abu Sisi, however, says he has been interrogated about other issues, not about Shalit.

Foreign media outlets have disseminated reports about the apparent flight route by which Abu Sisi eventually reached Israel. An engineer at the only power station that operates in the Gaza Strip and the holder of a Jordanian passport, he left Gaza for Egypt, and then entered Jordan. He has told relatives that while in Jordan, his departure was delayed for seven days, and he was compelled to report for questioning at offices of the Jordanian internal security service.

He was eventually allowed to depart for the Ukraine, where he was headed to finalize his request for citizenship in that country. Abu Sisi is married to a 32-year-old woman who holds Ukrainian citizenship; they have six children together.

Abu Sisi has also suggested that the flight from Kiev involved a stopover at some unknown site, and then a half-hour flight to Israel. If his account is reliable, the aircraft may have stopped in Amman, Jordan, or possibly Cyprus.

According to his wife, Veronica Abu Sisi, he was captured by two uniformed men, and one man in civilian clothing, while traveling on a train in the Ukraine.