Final answer:
The four items most likely disturbed by an eyewitness at the crime scene are the drapes, bedroom door, table lamp, and the open window, which all suggest an eyewitness's presence and possible interaction with the surroundings during the crime.
Step-by-step explanation:
Investigators looking at the crime scene described will consider items that appear out of place or disturbed, as these might have been affected by an eyewitness during or after the crime took place.
Given the scenario, four items that seem likely to have been disturbed by an eyewitness are: the drapes in the living room being wide open, possibly opened by the eyewitness to get a better view or to attempt an escape; the bedroom door being ajar, which could indicate the witness or the perpetrator moving between rooms; the table lamp lying on the floor in the bedroom, suggesting a struggle or a sudden movement that an eyewitness might have caused while hiding or escaping; and the window being wide open in the bedroom, possibly used by an eyewitness or the perpetrator as a means of entry or exit.
These disturbances are potential signs of the movements and actions of an eyewitness during the crime.