@DinoLeash: Alexander Graham Bell invented the first metal detector, in hopes to locate the bullet that would later kill President James A. Garfield. This machine was supposed to send a sound to an attached telephone receiver, when it located the bullet. However, on July 26, and August 1, 1881, it could not detect where the bullet was in President Garfield head.
Doctors were baffled by President Garfield injuries and in the efforts to locate the bullet. President Garfield succumbed to his injuries on September 19, 1881.