The police rounded up Jim, Bud and Sam yesterday, because one of them was suspected of having robbed the local bank. The three suspects made the following statements under intensive questioning.

  • Jim: I’m innocent.
  • Bud: I’m innocent.
  • Sam: Bud is guilty.

If only one of these statements turns out to be true, who robbed the bank?

Communicated by G. Mejia.