Talking about it would have painted a huge target on his back for retribution from the Iranian government. It would have also put a target on his wife's back, as well as all of her family that is presumably still in Iran. Killing him also would make it much harder to recruit assets in the future, if it became common knowledge that you will be offed after your mission is complete.

It seems much more likely that he actually did die in a random motorcycle accident (not uncommon), or he was entirely uninvolved and a dead man was chosen to pin blame on in order to hide the real method(or, to make Iranians stop trusting foreign contractors, making them do everything in-house with higher costs and worse quality).