Answer:
DNA samples taken from the hair and blood found on the floor
Step-by-step explanation:
Since there was a struggle between the victim and murderer, it is possible that the hair and blood found on the floor belong to the murderer. DNA samples taken from hair and blood could be used to generate DNA profiles using DNA fingerprinting technique which was developed in 1984.
By comparing the NA profiles made using DNA from hair and blood on the floor with DNA profiles of suspected killers, it is possible to identify the murderer.