“Can’t help that,” Newton Mills smiled a dry smile. “Bullets don’t lie, not to me.
“What is more—” He laid a hand on the other gun, the one that had been taken from a murderous hand on the deserted slip on the night Johnny shot an arrow, “this is the gun that killed Rosy’s father. It is also the gun that fired the shot in the studio on the night that Johnny was beaten up.”
The two boys stood there for some time, silent, dumfounded by such startling revelations.
“Since you know this much,” the Old Timer went on at last, “you may as well know the rest. Let me explain to you how it is that I can know these things with such certainty. I will explain it to you just as I would to a jury. May take a little time, but in view of the large place this new science of forensic ballistics is sure to play in future detection of crime, I am certain it will be time well spent.”
There was a tap at the door. Mrs. Ramacciotti appeared with the morning coffee.
“Good!” exclaimed the Old Timer. “Coffee and bullets. What could be sweeter!
“Forensic ballistics,” he said musingly as he sipped hot coffee, “sounds rather impossible, doesn’t it? It means only this. Forensic, having to do with the law; ballistics, the science of projectiles. Forensic does not interest us. Ballistics, for us, means the science of bullets.
“Now,” he said, reaching for Jimmie’s automatic and glancing down its barrel, “you know that the barrels of revolvers are rifled; that is, there is a series of spiral grooves running through each barrel. That is done to make the bullet go straight. A smooth surface causes the bullet to tumble end over end the instant it leaves the gun.”
Taking three small white sacks from his bench, he emptied their contents on the table before him: three bullets.
Displaying two of these on the palm of his hand, he asked: