I can't be precise hence I have overloaded the question with pics
As the title asks, when Barry went back to the past in The Flash, a series of events happened. One was Cisco discovering that Dr. Wells faked the whole scene with the yellow-suited Flash (see image below)
and it was actually Dr. Wells who was the man in the yellow suit. In the process of the discovery Cisco got caught and Wells killed Cisco in the process.
However when the series came back to present time Cisco still had memories, eventually Cisco and Barry came to the conclusion of re-framing the whole scenario so as to get Dr. Wells to confess that he indeed killed Barry's mother so as to be apprehended, but in the recreation of the scene Dr. Wells sent the ShapeShifter [image 5 is the shapeshifter] to represent him (Dr. Wells). The recreation took place however it wasn't Dr. Wells (as you can see his hands are not vibrating). The dialog was exact.
My question is, how did Dr.Wells know about something that has not taken place? (The event happened in the past and barry went back to change the fact, hence the future was changed successfully, meaning it did not happen at all.)
To support my question of how Dr. Wells knew about something he didn't, in the final episode of The Flash season 1 Dr. Wells was captured and incarcerated. Cisco approached him about what he said (in the moment that never happened) and he wanted to know how he feels about it. Dr. Wells' reply was that he is clueless of what happened, but if he killed Cisco in the process then he had a good reason, meaning he didn't even know why he killed Cisco. Hence the question.