The United States is one of the reasons for this heartbreaking incident. The US had imposed an embargo on the sale of any aircraft to Iran. Because of this the President and his associates had to be martyred. This crime of America will be recorded in the memory and history of the people of Iran. America had no role in the crash of this helicopter.
Can you tell in details on what reason the US palced an embargo on the Iranian government prohibitedly on the purchase of aircrafts? I'm totally unaware.
You may actually have got things twisted because you're directly an indirectly saying the US is responsible for the helicopter crash and other hand that the US has no role to the crash of the same helicopter. So if I should go by your thought, literally Israel as suspicious hands may be pointed at would then not take the blame, huh? And should be accepted that it was accidental aviation incident.
But While experts are still undergoing research, let all hands be folded without the accuses and keep eyes on the watchlist.