You've been called to the scene of a murder. The lock on the victim's apartment door was broken, likely by a crowbar found in the doorway. The victim was found lying face down on the floor with a bullet in his back. Based on the condition of the apartment, it appears a struggle occurred between the victim and the murderer. There are several drops of blood located in the nearby kitchen, as well as a broken glass on the floor. Assuming this situation occurred in the late 1800s, which relatively new type of evidence would most likely be used to identify the killer?
DNA samples taken from the hair and blood found on the floor
Motives of possible suspects based on information from the victim's wife
Fingerprints found on the crowbar and on the glass
Information obtained after examining the bullet under a comparison microscope