"This is a complex security affair, which needs to be investigated not only in Israel, but also in other countries, and therefore the investigation takes time," Judge Dan Arbel, president of the Tel Aviv Magistrates Court, said April 16 in deciding to permit publication of Manbar's detention.
The judge did not reveal any details about the investigation, but he warned at the time that "the suspect may face a grave penalty of many years in jail" if the allegations against him are proven true.
This week, Manbar, 51, was charged in Tel Aviv District Court with aiding Iran, trying to damage state security and obstruction of justice.
Sections of the charge sheet released for publication said that from 1990 to 1994, Manbar supplied Iran with raw material to make mustard and nerve gas.
Manbar, who faces up to life imprisonment if he is convicted of aiding an enemy of Israel, is maintaining his innocence.
Questions also linger about the circumstances surrounding his initial disappearance because it was not without precedent.
Several other Israeli citizens have disappeared for lengthy periods before it was learned that they were held by Israeli security services.
These secret detentions have raised concerns among some in the legal and political community.
"This is a stain on our democracy and our legal system," said Moshe Negbi, a legal analyst.
Zvi Aharoni, an ex-agent at Shin Bet, Israel's domestic intelligence agency, once told the daily Ma'ariv that "there is a hysteria in Israel to hold people in secret detention, even when it's not necessary."
Among those held secretly were:
*Motke Keidar, who was involved in the Lavon Affair, in which Israelis conspired in the mid-1950s to bomb an American library in Egypt in an effort to sabotage Egyptian-American relations. He was held secretly for 17 years in a prison cell. Other prisoners called him Mr. X because they did not know his true identity.
*Marcus Klingberg, a Tel Aviv University professor, was arrested and secretly sentenced in 1983 to serve 18 years in prison for spying for the Soviet Union. His case first surfaced in the British media in 1987, and later in German reports.
An Israeli news blackout was lifted in 1993, but details about the Klingberg case remain unclear. According to Israeli reports, Klingberg immigrated to Israel in 1948, and was last seen in January 1983 en route to a scientific convention in Western Europe.
*Mordechai Vanunu, a technician employed at Israel's nuclear facility at Dimona, disappeared in 1986 and later reappeared in an Israeli jail. Vanunu was lured from London to Rome in 1986 and kidnapped by Israeli agents, who brought him to Israel.
He was sentenced in 1988 to serve 18 years in prison for disclosing Israeli nuclear secrets to the London Times.
Under Israeli law, a judge can order a total ban on any details relating to the arrest of someone. At the request of police, a judge is authorized to prevent a meeting between the suspect and a lawyer for 14 days.
In contrast to the others, Manbar's disappearance was brief.
Manbar was born on Kibbutz Givat Brenner, and after completing his army service began a business career. He left Israel in the mid-1980s with only $600 in his pocket, and became a millionaire.
He lived in a villa in St. Paul de Vence on the French Riviera, with his wife and two children. They have moved to Switzerland.
Manbar reportedly began to make significant money after he met with Iranians in Vienna in the early 1990s. According to reports, he allegedly struck a deal by which Russian tanks and other military equipment destined for Poland were forwarded to Iran.
U.S. intelligence reportedly detected that Manbar had sold Iran parts of nonconventional arms. By 1994, the Israeli was banned from entering the United States and American firms were warned not to do business with him.
Meanwhile, Israeli security services warned friends of Manbar to stay away from him, without specifying why.
Manbar's friends have insisted that his dealings with Iran took place with the full knowledge of Israeli authorities, and that when he was warned in 1993 to end those ties, he complied.
But security sources have maintained that "Manbar had sold his soul to the Iranian devil."
This week's indictment alleged that Manbar met several times with the head of Tehran's chemical warfare project, signed a contract and received $16 million.
Manbar allegedly told Israeli intelligence officials at the end of 1991 that he had contacts with Iran but did not raise the matter of the chemical arms sales.
But, in 1992, Israeli intelligence acquired information that raised their suspicions of his role in Iran's chemical weapons development.
Manbar allegedly told Israel he would stop, but didn't until 1994.