Segev allegedly communicated with his operators through a "secret communications system to encrypt messages" and supplied Iran with "information related to the energy sector, security sites in Israel, and officials in political and security institutions".
In February 1994, Segev split from his righwing Tzomet party to eventually become Minister of Energy and Infrastructure in PM Yitzhak Rabin's government.
He was jailed for five years in 2005 for trying to smuggle tens of thousands of ecstasy tablets into Israel from the Netherlands and was released two years later.
Security authorities had gathered intelligence indicating that Segev was maintaining contacts with Iranian intelligence and assisting them in their activities against the State of Israel.
According to Shin Bet, Segev himself approached the Nigerian Embassy in Abuja and offered himself up as an agent.
According to Gonen's lawyers, "the indictment paints a different picture than the Shin Bet statement".
Prosecutors said at the time of his arrest, Segev was an active agent and had traveled twice to Iran to meet handlers.
The disgraced former politician, who was a member of the Tzomet and Yiud parties, has been living overseas since being released from prison after he was found guilty of drug smuggling in 2006. More recently, Israeli forces have carried out a number of airstrikes on Iranian forces in neighboring Syria. In 2016, Segev filed a request to have his Israeli medical license reinstated in order to be able to return to Israel.
Segev's legal representatives, Adv. Eli Zohar and Adv. Moshe Mazor from the Goldfarb Seligman & Co. law firm, stated in response, "We have been advising Mr. Segev since he arrived in Israel a month ago".
Public Security Minister Gilad Erdan said that if Segev is convicted of the offenses attributed to him, he must end his life in prison. He left politics after losing his seat in the 1996 elections.