I thik so!
I just did some testing on a saved game.
To make the story short, out of 99 tries, I targeted 33 times assassin(16%), diplomat(25%) and stayed idle- 66 times my assassin is KIA. In subsequent turn, a heretic always spawns nearby (various chances, 50 to 75%). Imam I sent on him is always turned to heretic and assassin dies (33 times idle in the first turn).
It is vanilla medieval 2, all i did to it was changing the timescale.