Iran's late President Ebrahim Raisi's helicopter crashed because it was carrying more passengers than it was rated for.A security source told Iranian media outlets about the findings from the final investigation of the crash. Reports said the helicopter was carrying two extra passengers and the crash in the mountains.((GFX TEXT: “The investigation in the case of Ayatollah Raisi’s helicopter crash have been completed ... there is complete certainty that what happened was an accident,” The Security source.))A preliminary report by Iran’s military had said in May that no evidence of foul play or attack had been found so far during investigations into the crash.