To me, this is curious.
When you throw multiple people into a well as a criminal act, my guess is you do it for several reasons; One, you don't want to dig holes. Two, you don't want the bodies discovered/recovered without considerable difficulty. Three, to make sure the well whether dry, or not can not be used for drawing water and Four, unlike a lynching which can be viewed from a distance and the dangling body serve as both a trophy and a lasting warning, you don't want your act seen from a distance.
If the person is alive at the time you throw them in, you are also seeking to inflict a measure of pain and suffering on the hapless person as well as intimidate fellow mob members and onlookers.
The only way I could see these people being thrown in as a non-criminal acti is if they had already died of disease, famine or fire. If that was the case, the only reason for throwing them into a well would be because the well had long been known as being dry and offered the quickest means of disposal.
The question for a history detective should be:
1144 riot after William of Norwich died. First Blood Libel in Medieval Europe.
Do you smoke a pipe and wear a deer stalker hat?
Thanks fso301.