It's dusk and you have just commited a horrible murder. The only three people who have witnessed the crime are a half-blind man, a deaf woman and a three year old toddler. The half-blind man has an incredibly keen ear and is more than able to recognize your voice especially since you yelled "DIE YOU SON OF A *****!" so loud that the whole country could have heard it. But his eyesight is lousy and he is just about to put on his thick lensed spectacles so you are not sure whether he will still be able to identify you. The deaf woman was standing a good hundred yards away from when it happened but she has exceedingly flexible eyesight. She managed to witness the whole scene even in the dimming light of dusk. Lastly the toddler whose eyesight and hearing are presumed to be normal has caught a good glimpse of your face. He may not be able to squeal on you now but there is a fair chance he may be able to help track you down in the future.
You cannot escape the city because you have no money and all the exits are guarded by the militia.
You have the chance to perform one memory removing magic spell on one of these people before the cops catch you themselves. The spell will make one of them forget about the whole incident. Whose memory would you erase?
