Mukhtasar Bukhari (Abridged) 1304 — What to do if a hostile

Saidna Salamah bin Akwa’ (may Allah be pleased with him) narrates that a spy from the polytheists came to the Prophet (peace and blessings of Allah be upon him) while he (the Prophet) was on a journey. He (the spy) sat with the companions (may Allah be pleased with them) of the Prophet (peace and blessings of Allah be upon him) and started talking. After that, he left, so the Prophet (peace and blessings of Allah be upon him) said: “Catch him and kill him.” And the Prophet (peace and blessings of Allah be upon him) gave his belongings to the one who killed him.