Yes appoint a special prosecutor at the very least.
Someone independent who is allowed to investigate
That isn't going to happen. He supposedly died in 2019. Any special prosecutor should have been appointed then, and there's a reason one wasn't. There likely isn't any real evidence left to even conduct an investigation, especially any related to his being a government or Mossad asset. FBI and CIA were likely involved using him as an asset. Both of those agencies and the Mossad have a history of hiring unsavory characters from the day they were created.