A “Toolbox” for Forensic Engineers

370 Forensic Materials Engineering: Case Studies
sell boxes of cartridges to a wide variety of outlets. Thus sportsmen thousands
of miles apart could be using shotgun cartridges containing pellets made
from the same kettle of metal in the same shot manufacturing plant on the
same day.
As the Crown’s case against the accused depended almost entirely on the
analyst’s conclusion that the pellets on the letter were from the same cartridge
as those in the fatal wound, the jury not surprisingly reached a verdict of not
guilty.
12.3 Metal Theft
Nonferrous metals are of considerable value and many small enterprises make
a living by collecting scrapped items at source and selling them to scrap
merchants who sort and regrade them before sending them to refineries. At
the very bottom of this pyramid are individuals who ask no questions about
the source of their scrap and who make their living by selling it to the highest
bidder. This case concerns one such individual who made a gross mistake.
An electroplating firm ordered 9 t of copper cathode from a copper
refinery. This is a pure form of copper that is produced only by electrolysis;
the cathodes are somewhat irregular, 5 to 10 mm thick, with a smooth surface
on one side and numerous tiny nodules standing proud on the other, as
illustrated in Figure 12.3. This sample is a piece of cathode of similar size to
Figure 12.3 Piece of copper cathode approximately 30 mm 2 , ex-refinery. Notice
nodules on the surface and along the right-hand side, which formed the edge of
the cathode in the electrolysis bath.