A “Toolbox” for Forensic Engineers

Criminal Cases 371
those stolen and is much larger than the guillotined pieces that it was to have
been cut into for the electroplating process. It is included here to show the
characteristic nodules on the surface as well as along the edge at the righthand
side. Freshly produced cathode is a bright salmon pink color when it
leaves the refinery but oxidizes to a dull brown after a few weeks. For use as
anode in barrel electroplating the cathode has to be reduced to small pieces
about 25 mm 2 , so the electroplating firm needed to send its metal to another
firm that had a powerful guillotine. The electroplating firm arranged to have
this done on a Monday but, because the consignment arrived late on Friday
afternoon, the truck was driven inside the plating firm’s yard and the gates
locked. It was not visible from the outside. On Monday morning when the
gates were opened up the truck was gone, and with it 9 t of copper worth
more than £9000.
The nonferrous metal trade has a system of notifying all dealers and
metal merchants of a theft and the nature of the material stolen. Some 4 to
5 days after the theft a small van drove to a scrap dealer 250 miles away from
where the truck was taken. The driver offered to sell a quarter ton of scrap
copper, saying he had more if the price was good enough. The scrap merchant
realized that in the load of mixed copper — a few old hot water cylinders,
pipes, wire, and so on — were pieces of cathode, so he purchased that load
and offered to buy all that the driver could deliver. He also notified the police.
Within an hour the driver was back with another quarter ton, most of which
was cathode. He was arrested and the police accompanied him back to a
small yard where they found the stolen truck containing just over 8 t of
copper cathode.
The man arrested claimed that he was just a small-scale scrap dealer, who
had bought all the metal in small lots from local housing estates and small
industrial units. It hardly needed a metallurgist to identify it as ex-refinery
cathode, which is totally different from swarf or clippings arising from manufacturing
processes, or discarded items from plumbing systems and electrical
wiring. The thief was obviously unaware that the only uses for cathode
copper are in electroplating and for remelting and alloying with other metals.
In no way could the metal in his possession have been collected from housing
estates and light industry. It was particularly incriminating that the total
amount was 9 t and was just starting to develop the brown oxide coating. It
could only have emanated from the one refinery still operating in the U.K.,
and its color was consistent with it having been produced some 3 to 4 weeks
before it was recovered. Further inquiries revealed that the man arrested had
been living with his family in a caravan not far from the refinery at the time
of the theft.
Another case of theft that required examination of coarse pieces of swarf
found in the soles of a suspect’s boots has already been referred to in Chapter