There is a lot of controversy surrounding the accuracy of eye-witness reports of events. Human memory is quite inaccurate and vulnerable to alteration. The simple phrasing of a question by an examiner can lead the witness to believe something happened that didn't. For example, notice the difference between these two phrases:
"Where did you see the car smashinto the other car?"
"Where did you see the cat hitthe other car?
The first statement can cause the witness to remember the impact as more violent than it was, and the second statement can cause the witness to remember it as less violent than it was.
The information that we receive from our senses is filtered through our past experiences. As such, the experiences of the witness can cause them to misremember events by putting together incoherent facts into a tell-able story that has been filtered by experience not by an accurate recollection of events.