The prisoner had given information that a burglary was to be committed, and had, "in the interests of justice," taken part in it himself. When he was captured he was on his way to take the stolen property to the police-station, and the information he had given had enabled the authorities to secure the other men. "The prisoner was discharged." If you read between the lines of this story you will have a fair idea of the way in which the professional "nark" works in connection with what—at least, so far as he is concerned—is a put-up job—a trap deliberately arranged for the capture of a criminal.
When a sensational crime has been committed by confederates or by a "gang," and the hue and cry continues unabated, it sometimes happens that one of them tries to make himself safe by offering information to the authorities on certain well-under-stood conditions.
"King's evidence" is recognized as a necessary evil, for it is occasionally the only evidence upon which a conviction could possibly be obtained. Turning King's evidence does not always save the traitor. He may escape the punishment of the law, only to meet with a tragic fate at other hands. Carey, one of the informers at the Phoenix Park murder trial, was got safely away, only to be shot dead by Patrick O'Donell on board a steamship near Port Elizabeth, South Africa.
Other informers less notorious met with "fatal accidents" in far-off lands. Two who went to Paris and lived under assumed names came to the Morgue. They were "found drowned" in the Seine.
The informer in the great bank-note forgery case was doomed to death by the men whom he had betrayed. The revolver with which the elder Barmash committed suicide after sentence had been passed upon him was intended to be used upon the informer who stood in the dock a fellow-prisoner. The opportunity of shooting him did not occur. The man was never in a position in which he could be safely aimed at.
But the informer is not always called upon to make a public appearance. Many of the tales we read about the marvellous discovery of a clue by the police would be shorn of their romance if we knew that an important fact was being kept in the background—viz. that the detective in charge of the investigation had received a communication informing him exactly where to look for the incriminating piece of evidence.
Sometimes the information is anonymous. A few words scribbled on half a sheet of notepaper brought two men to the gallows. The writer suggested that a visit should be paid to a certain house where a little boy would be found who had lost a toy. The hint was taken, and the tale the child told of his missing toy led to one of the most sensational captures of modern times.
Nothing was said about the information that furnished the police with the clue. There was no necessity to tell the story, or to produce the anonymous letter. Yet, but for that hint, it is probable that the crime would have remained one of the unfathomed mysteries of the Metropolis.
A year or two ago a foreign woman was tried for murder. The evidence—although the body of her victim had been concealed in a trunk—justified a verdict of manslaughter, and the woman only got a term of penal servitude.
For two years this woman had been of the greatest assistance to justice. She had become associated with a dangerous class of women in a West End district, and when a man had been robbed by one of them, or by men acting in concert with them, this foreign woman made it her business to find out who the guilty parties were, and to send their names to the police.