In a recent televised program on BBC 2, Hashemi Rafsanjani was also interviewed. In his interview, Rafsanjani said that when Khomeini died, the Islamic Republic had to choose a Vali-e-Faghih. According to Hashemi rafsanjani, there was no one and Khomeini had not appointed anyone before his death. He said (paraphrase) however, two people who were always with him in private were himself and Khamenei. When the Majles-e-Khobregan had to choose a Vali-e-Faghih, he told the Khobregan that during one of his private meetings with Khomeini they had brought up the issue that Khomeini had not chosen his successor. To which Khomeini said to them (Rafsanjani and Khamenei) that Khamenei should be appointed as his successor. The program showed a clip where he actually talked to the Khobregan and told them what Khomeini had said during that private meeting and suggested that Khamenei should be appointed. After his suggestion, the majority of the Mullahs and Ayatulahs in Khobregan voted for Khamenei as they believed Rafsanjani. After Ahmadinejad was appointed as the President of the Islamic Republic, Ahmadinejad started to throw his weight around and threatened to expose and even bring to justice - no matter what position they had in the Islamic Republic - those who had through corruption and abuse of their positions mounted wealth and power. Everyone knew who he was referring to. He was talking about Rafsanjani. Rafsanjani's relationship with his old mate Khamenei was also strained at the time. Rafsanjani, in return threatened to reveal some facts that would rock the regime. Ahmadinejad never took any further action against Rafsanjani and things calmed down.
What Rafsanjani said wittingly or unwittingly in that interview broadcast by BBC 2, in my opinion, is what that secret revelation was: the fact that Khamenei was appointed because Khobregan was influenced by that suggestion and that's how Khamenei is now the number one power in Iran.
Rafsanjani lied about Khomeini suggesting Khamenei as his successor.