Altered from how it should have originally looked like.
In this case, I remember one interview of DC. He was standing on the bridge. The way I understood him, what he said was, he gave the CS one look and felt nauseated, so I assume there must have been something nasty there.
The previous poster assumed that maybe, the person who saw the girls did not see the deers (assuming, the girls were standing?). I think, not, because the CS was not easily seen.
Okay, "anything altered" is not the definition of staging that homicide investigators work with.
Laura Pettler, the criminologist who literally wrote the book on crime scene staging in homicides, defines staging as: "Crime scene staging is the physical manifestation of a person’s imagination for how things should appear when trying to turn a murder scene into a legitimate death scene.” This is from her book "Crime Scene Staging Dynamics in Homicide Cases."
Aspects of the scene that are altered because they brought the offender pleasure or psychological fulfillment are not included in the definition of "staging." So just because a crime scene was violent or nauseating to investigators, it does not immediately follow that staging - which alters the crime scene specifically to confuse the nature of the crime - has occurred.
The task of LE in figuring out which aspects of the scene might reflect staging and which do not, is a job with many pitfalls but Pettler says that a thorough and accurate victimology will normally uncover it.