What forensic scientist discovered how to use a comparison microscope to match bullets found at a crime scene?

comparison microscopes are used to identify a specific weapon.

every gun weapon, has a unique pattern on the bullet after firing.

authorities can compare a murder weapon with the same stock of gun.

if murder weapon is found, they can compare the "murder bullet" with existing guns of the same make, model, if while finding the murder weapon, the same pattern exists on suspected weapon's bullet, it will be subjected as evidence.