evidence of the police detective is received with so
much suspicion by jurymen--they know that the only way for him to retain
his position is by making a record and getting convictions, and hence
they are always looking for jobs and frame-ups. If a police detective
doesn't make arrests and send a man to jail every once in a while there
is no conclusive way for his superiors to be sure he isn't loafing.

There are a very large number of persons who go into the detective
business for the same reason that others enter the ministry--they can't
make a living at anything else, Provided he has squint eyes and a dark
complexion, almost anybody feels that he is qualified to unravel the
tangled threads of crime. The first resource of the superannuated or
discharged police detective is to start an agency. Of course, he may be
first class in spite of these disqualifications, but the presumption in
the first instance is that he is no longer alert or effective, and
in the second that in one way or another he is not honest. Agencies
recruited from deposed and other ex-policemen usually have all the
faults of the police without any of their virtues. There are many small
agencies which do reliable work, and there are a number of private
detectives in all the big cities who work single-handed and achieve
excellent results. However, if he expects to accomplish anything by
hiring detectives, the layman or lawyer must first make sure of his
agency or his man.

One other feature of the detective business should not be overlooked. In
addition to charging for services not actually rendered and expenses not
actually incurred, there is in many cases a strong temptation to betray
the interests of the employer. A private detective may, and usually
does, become possessed of information even more valuable to the person
who is being watched than to the person to whom he owes his allegiance.
Unreliable rascals constantly sell out to the other side and play
both ends against the middle. In this they resemble some of the famous
diplomatic agents of history. And police detectives employed to run down
criminals and protect society have been known instead to act as stalls
for bank burglars and (for a consideration) to assist them to dispose of
their booty and protect them from arrest and capture. It has repeatedly
happened that reliable private detectives have discovered that the
police employed upon the same case have in reality been tipping off
the cri