The suggestion that Iran is behind such a plot is ridiculous and baseless. It is deeply unethical that Iranian citizens would potentially be targeted because of false accusations that Tehran unequivocally denies. Washington should instead focus its efforts on re-negotiating the 2015 nuclear deal on fair terms.
There are plenty of reasons why the US should not deal with the Islamic Republic, and this is another example of Iran's duplicity. How can the United States sign a deal with the regime in Tehran in good faith when Iran continually threatens to assassinate high-ranking US officials?
Though this alleged plot is deeply concerning, the likelihood of prosecution going anywhere is almost zero. Besides the fact that Poursafi is almost certainly safe in Tehran, this is not the first time Iran has plotted to kill US officials, with the US avoiding a direct response to such threats.