I believe I heard somewhere this was started by a bird strike.
And not to defend Boeing, but they don't make the engines. The engine is a CFM56 made by CFM International. The same engines are used on some Airbus a320s, Airbus a340s, and McDonald Douglas DC-8's
They tried a similar one on me once. Sent a email saying my boss (by name) sent me a virtual gift card. I immediately knew it was one of their "phishing tests" as my boss is a giant douche who would rather take the time to throw me under a bus than do anything that nice.