The district attorney brought a small bottle from his pocket and shook some grayish powder into a paper on the table. Then he took a camel’s-hair brush and began applying the powder to different spots on the leather chaparajos.
“It is what is technically known as gray powder,” he explained. “It’s made of charcoal, chalk and mercury. A little of it will bring out a finger print with amazing clearness. Here are some that don’t belong to the boy.”
Under the application of the powder several finger prints stood out clearly. Taking out the paper which Bertram had handed him, the district attorney compared the prints.
“Fate seems to have helped us out,” he said finally. “It might be a matter of some time and difficulty in checking up these finger prints, under ordinary conditions. There are four general classes, known as arches, loops, whorls and composites—self-explanatory names. But there are over a thousand types, and checking up without a complete set of finger prints is ordinarily a matter of difficulty. But right here is where Fate, as I say, seems to have helped us.”
The district attorney called Bertram’s attention to two tiny spots, almost in the center of the thumb print, on the paper which had been attached to the Texan’s cabin, and a print which the powder had brought out clearly on the leather chaparajos.
“The man that made those thumb prints might have been struck in the ball of the right thumb by a rattlesnake, at some time in his life. Anyway that is what we will assume. There are two small scars, just big enough and deep enough to change the swirl of the thumb marking, almost at the very center. Those markings, no matter what type they may fall into, never become confused naturally. In other words, those tiny corrugations never cross each other, unless by accident of an external nature. Such an accident has happened in this case. The peculiarity of this thumb print can be distinguished with the naked eye.”
“Let’s see if there isn’t another on the rifle,” said the Texan. “We can’t be too dead sure about this business.”
An application of powder to the boy’s rifle brought to light several other thumb prints, showing the rattlesnake scar.
“A man who was used to handling guns would pick up the boy’s rifle just by instinct,” said the Texan. “The man that shot Jimmy picked up the lad’s .38, and he probably worked the lever once or twice, explaining the unexploded cartridges that were found on the ground. It’s second nature for a gunman to do anything like that.”
“These prints on the rifle are even clearer than the ones on the leather,” replied the district attorney.