This morning we told you about the rash of mysterious "Arabic" graffiti appearing on the underside of Southwest Airlines planes recently, which has prompted an FBI investigation. Now, a tipster has sent us actual photos. Cower in fear!

According to our tipster, a Southwest employee who has seen these markings multiple times: "They are on the exhaust pipe of the engines. Usually on the inboard side. And most of them are described as looking like swords. (picture an elongated "S" with a line crossing it toward one end.)"

Press reports have said the marks appear to have been "etched using a chemical process." But our tipster says, "To me they look less etched and more wiped on with grease."

The vague sword-shape of the markings is clear in these photos, which our tipster says were taken very recently. But... where did the "Arabic writing" bit come from? "I havent seen any 'arabic' writing either," says our source. "All the marks look like that 'sword'. I have seen one other plane that had a star with 3 horizontal wavy lines to the right of it. But Ive only seen it once."

So there you have it. It's up to you to decide how terrified to be. This is, after all, America.