Final answer:
The firearm found in the Texas School Book Depository was linked to Lee Harvey Oswald by using ballistic analysis. This method compares bullet marks, which are unique to each gun, similarly to human fingerprints. The marks on the bullets that killed President Kennedy matched those that could be produced by Oswald's rifle.
Step-by-step explanation:
The gun that was found in the upper stories of the Texas School Book Depository building was linked to Lee Harvey Oswald through ballistic analysis. Ballistic analysis involves comparing the bullets found at a crime scene, in this case, those that killed President Kennedy, with a gun suspected to be the murder weapon. Bullet marks are unique to each gun, much like fingerprints are to humans. The marks on the bullets matched those that could be made by the gun found in the depository, thus linking it to Oswald, an employee there.
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