I'm looking for a word that refers to what a witness would see. I considered 'observation', but I'm looking for something more pointed and implying focus. Does such a word exist? Many thanks!
Although a witness does observe, an observer does not always witness. According to Hindu philosophy, a witness is described as one "who is here to observe and enjoy this world of objects, unending perceptions and wonderful creations, without becoming attached to them" (Jayaram V, Hinduwebsite.com). This suggests a personal relationship between the observer and that which is observed or witnessed.
As such, a witness not only observes, but perceives, which suggests awareness and appreciation of what is being seen. So, perhaps Perception would mean more than Observation in your context.
If a witness happens to be where a crime (defined as criminal activity) is committed, he/she will see a crime (being committed) or a crime scene and they are broadly used.
Scene is defined in Merriam-Webster as:
a part of a play, movie, story, etc., in which a particular action or activity occurs
The drama, CSI, stands for Crime Scene Investigation and the actors investigate a crime scene.