The conclusion that the investigator should make after making the observation is that the bullet did not leave the victim's body.
Since the investigator realized that there was actually a gunshot wound in this scenario, the fact that there was no blood spatter does not disprove this fact.
Thus a reasonable conclusion that the investigator can reach is that the bullet never left the body of the victim.
Learn more about investigations here:
https://brainly.in/question/1660450