Three to Conquer by Eric Frank Russell

intent. "But what he can do is exactly what we're trying to get him to do right now. He can look at three pictures, give the nod and start the hunt. There's only one sure way to prevent him, and that is by closing his trap for keeps before it's too late."
     
                  "That's clear enough reasoning," said Jameson, "but it has one major flaw."
     
                  "What is it?"
     
                  "All the news .channels have publicized details of both the Alderson and Whittingham killings. Everyone from coast to coast knows that you're wanted for the latter, and suspected of the former. The three fugitives know that they fit in this picture and that, in any event, your witness's description of them would fit a thousand others. There's nothing whatever i n the news to suggest the remotest likelihood of a witness being shown photographs dug out of confidential files in Washington. So why should they deduce that possibility ?" '
     
                  "Because I shot down the Whittingham girl."
     
                  "I don't understand," confessed Jameson, frowning.
     
                  "Look, I've given you the facts as I saw them. They picked up that girl for some reason or other—probably because the opportunity presented itself, and they wanted to try their technique. Anyway, they turned her into another of their own kind. She ceased to be Jocelyn Whittingham, but continued to masquerade as such. Don't ask me how it was done because I don't know, and can't guess."
     
                  "Well?"
     
                  "The big question now is: were they able to lea rn and remember that girl's Earth-identity? Or was it something they failed to record—either because they viewed it as of no consequence, or because it -was incomprehensible to them?"
     
                  "Go on," Jameson encouraged.
     
                  "If they don't know her identity, the news of her death will mean nothing to them. It will look just like any other sordid murder, and they won't realize that they're linked with it in any way. But if they d o know her identity—"
     
                  "For crime's sake, don't keep me in suspense," pleaded Jameson.
     
                  "The killing will get them onto their roller skates and going at top speed. They'll want to know why she was killed. They can see with half an eye that real knowledge of their presence will inevitably be linked with that space-expedition, and they'll be eager to find out whether there's time to break the linkage by cutting a couple of throats."
     
                  "Including yours."
     
                  "Yes. I'm the sacrificial goat. The news-channels have shouted my name and address all over the shop, and invited them to come and get me—if they can. It won't be a quick death, either."
     
                  "What makes you say that?"
     
                  "So far as I can guess, they've one weapon, and one only — but it's a formidable one. They can double as human beings, without possibility of detection except by some freak like myself . It's of the greatest importance to them to find out how I did it; they can't counter, a menace without knowing the nature of it. They will have to get the truth out of me in any way it can be done. Otherwise, there's no telling how many more people can tag them, or when the next moment will be their last. Their lives wouldn't be worth living."
     
                  "Telepaths aren't ten a penny," Jameson pointed out. "You've said so yourself."
     
                  "But they don't know that. They're left guessing, in circumstances where no guess is too farfetched. To them, it might well be that every red-haired human can smell them — and there are a deuce of a lot of redheads around. They've got to know how it's