Question: who warned about the trojan horse?
Answer: While questioning Sinon, the Trojan priest Laocoön guesses the plot and warns the Trojans, in Virgil's famous line Timeo Danaos et dona ferentes ("I fear Greeks, even those bearing gifts"), Danai (acc Danaos) or Danaans (Homer's name for the Greeks) being the ones who had built the Trojan Horse.