This is an alert by guards produced with Agent 47 has a high notoriety level. In this example, it was at 66/100. Level: Flatline Learn more about the Notoriety system on the Hitman Wiki: hitman.wikia.co... ---
Low notoriety (upto about 50%) makes you more suspicious to guards if you stand still close to them for few seconds. High notoriety will give random npcs the ability to recognize 47 as the killer from tv. This could happen instantly or by them running to a newspaper.