Today
the
police
are
able
to
____________________
use
of
all
kinds
of
scientific
and
technological
aids
in
their
____________________
against
crime
.
This
was
not
always
the
case
,
however
.
In
the
early
days
of
the
British
police
force
,
during
the
nineteenth
century
,
the
police
officer's
whistle
was
his
____________________
way
of
calling
for
help
if
he
got
into
____________________
.
Gradually
,
in
the
twentieth
century
,
things
____________________
to
improve
.
Those
police
officers
lucky
enough
to
be
____________________
a
patrol
car
rather
than
a
bike
could
also
take
____________________
of
radio
communications
.
In
1903
,
a
new
system
for
identifying
people
by
their
fingerprints
was
discovered
.
____________________
,
it
soon
proved
to
be
one
of
the
most
significant
developments
in
crime
investigation
,
a
____________________
of
the
national
fingerprint
collection
could
____________________
days
,
if
not
weeks
,
until
computers
were
introduced
in
the
1970s
.
A
similar
problem
____________________
any
police
officer
who
got
the
registration
number
of
a
car
used
in
a
midnight
robbery
and
needed
urgently
to
____________________
____________________
who
owned
it
.
The
only
way
of
doing
this
out
of
the
office
____________________
was
to
phone
up
the
Police
Headquarters
in
London
.
They
would
send
an
officer
to
wake
up
the
caretaker
at
Country
Hall
,
where
the
records
were
____________________
.
The
two
would
then
have
to
go
____________________
an
enormous
card
index
system
in
the
basement
.
Today
,
police
officers
can
identify
the
____________________
of
a
vehicle
in
seconds
,
____________________
the
Police
National
Computer
.
