A “Toolbox” for Forensic Engineers

350 Forensic Materials Engineering: Case Studies
the premises, the redecoration had been completed, new carpet laid and a
new, larger radiator fitted. The homeowner produced the original radiator,
which had a hole near the bottom on the side facing the wall. The hole was
part way up the rear panel of the radiator, well above the bottom section
where sediments collect and pitting corrosion eventually leading to a perforation
tends to occur. Suspecting that this was not a genuine failure, the loss
adjuster sought a metallurgist’s opinion as to the origin of the hole. A piece
was cut out so that the inside wall of the radiator could be examined. The
wall exhibited a degree of internal corrosion consistent with several years’
service, but there was no significant pitting. The damning evidence, however,
was that the way the metal had deformed revealed the hole had been made
using a 3-mm-diameter punch with a sharp point, almost certainly an engineer’s
center punch. In addition, although the punch had penetrated the wall
at an angle it would not have been possible to drive it in while the radiator
still hung on the wall. Not surprisingly the claim was rejected and the insurance
policy canceled.
11.1 Car Keys
Modern cars and commercial vehicles are fitted with sophisticated electronic
remote door locking and immobilization systems, although generally all still
have a metal bladed key that is inserted into a barrel-type ignition lock to
start the engine. While most locking and immobilization systems can be
overcome by an expert with the right kind of apparatus they defeat the casual,
opportunist thief. Nevertheless, a large number of cars are still stolen, usually
when left parked or taken from garage or gas station forecourts when the
driver leaves the vehicle for a few moments to pay for gas, etc. The owners
invariably claim that they locked the cars before leaving them parked or, if
the vehicle was in a garage forecourt, that they took the keys with them when
they went to pay. When the claim is subsequently made, the insurance company
usually asks a loss adjuster to interview the insured and collect the keys.
Quite frequently the insured is only able to surrender one set of keys, claiming
that he or she had lost the second set or had only been supplied with one
set at the time of purchase. (This is sometimes claimed even when the car
had been purchased new only a few weeks before the theft!) Some claim that
the spare keys were kept inside the stolen car, without apparently realizing
that this defeats the whole object of having a second set of keys.
The forensic engineer is thus presented with one set of keys that are
claimed to have been the sole keys in use for the length of time the insured
owned the vehicle and for whatever mileage it is estimated to have covered,