said relates to the preparation for trial of cases where the
accused is already under arrest when the district attorney is
called into the case. If this stage has not been reached the
prosecutor may well be called upon to exercise some of the
functions of a detective in the first instance.

A few years ago it was brought to the attention of the New
York authorities that many blackmailing letters were being
received bearing the name of "Lewis Jarvis." These were of a
character to render the apprehension of the writer of them a
matter of much importance. The letters directed that the
replies be sent to a certain box in the New York post-office,
but as the boxes are numerous and close together it seemed
doubtful if "Lewis Jarvis" could be detected when he called
for his mail. The district attorney, the police, and the
post-office officials finally evolved the scheme of plugging
the lock of "Lewis Jarvis's" box with a match. The scheme
worked, for "Jarvis," finding that he could not use his key,
went to the delivery window and asked for his mail. The very
instant the letters reached his hand the gyves were upon the
wrists of one of the best-known attorneys in the city.

When the district attorney has been apprised that a crime has
been committed, and that a certain person is the guilty party,
he not infrequently allows the suspect to go his way under the
careful watch of detectives, and thus often secures much new
evidence against him. In this way it is sometimes established
that the accused has endeavored to bribe the witnesses and to
induce them to leave the State, while the whereabouts of
stolen loot is often discovered. In most instances, however,