It wasn't Iranian regime operatives.
It was a MEK member who was doing a false flag. Qui bono.
https://www.nbcnews.com/news/mideast/was-it-iranian-terror-plot-or-false-flag-operation-n889001
Of course the Mossad had the intel. They most probably directed the whole thing. But the good guys had intel too and prevented it.
MEK worked directly with Mossad to kill Iranian scientists.
https://rockcenter.nbcnews.com/_news/2012/02/09/10354553-israel-teams-with-terror-group-to-kill-irans-nuclear-scientists-us-officials-tell-nbc-news?lite
See graph.