The bullet from a suspect's pistol did not match the bullet found in a murder victim. There was blood on the carpet around the murder victim, but none on the suspect. The suspect's car was seen at the residence of the victim on the night of the murder. Carpet fibers from the room where the victim was found matched those found on the suspect.
Based on Locard's principle, which is a correct conclusion and why?

a. The suspect killed the victim with his gun.
b. The suspect was at the house because witnesses saw his car.
c. The suspect was in the room where the victim was found because of the matching carpet fibers.
d. The suspect killed the victim, which is known because carpet fibers on the suspect matched those in the room where the victim was found.

Locard's exchange principle states that the perpetrator of a crime will leave with something from a crime scene or bring something into the crime scene. These will be used as evidence to get the perpetrator.

From this question, option A is incorrect because the bullets on the victim did not match with the pistol of the suspect, hence Locards principle does not apply.

Option B is also incorrect because the car could have been driven there by someone else or could have just been parked there.

Option D is also incorrect because though the presence of similar fibre carpets on the victims appartment and on the suspect indicate the suspect was in the apartment, does not necessarily mean he commited the crime, he may have been there days earlier or he may have been there that day for other reasons.

Option C fits better.