How were the details of the Iran-Contra Affair discovered?

The Iran-Contra affair was discovered when a senior officer of the Mehdi Hashemi revealed the deal that was made. On November 3, 1986, a Lebanese magazine Ash-Shiraa published an article about the weapons agreement. The delivery of the weapons was discovered after a plane carrying the weapons was shot down and a survivor named Eugene Hasenfus was taken custody by Nicaraguan forces. In a press conference held in Nicaragua, Eugene disclosed that two of his colleagues Max Gomez and Ramon Medina were part of the Central Intelligence Agency. The article published by Ash-Shiraa was confirmed by the Iranian Government.