Studies by loftus and palmer, in which people were quizzed about a film of an accident, indicate that

I believe the answer is: people's recall may easily be affected by misleading information.

Films and accidents tend to happen really fast and even the witness near the crime scene couldn't fully grasp how and why the situation happened.

As it turned out, when they're asked about the situation, they tend to filled in the blanks with made up personal's opinion or other people's misleading information.