The Kid from Texas (1950)
Sheriff Brand: Suppose I told you there were half a dozen warrants out for his arrest right now. One for killing a man out of Silver City, Colorado, eight years ago with a knife. Another for killing four Chiricahua Indians.
Alexander Kain: Eight years ago? Well, that's ridiculous. The boy couldn't have been more than twelve years old!
Sheriff Brand: You don't judge a rattlesnake by his age. He's a rattler whether he's got one rattle or a dozen.