Yep it happened to PANAM in the 40s, and to Matson Airways in the 40s as was well documented in Ernie Gann's spectacular book "Fate is the Hunter."
It is for these and other similar cases that the "trust but verify" doctrine of mandatory 5-10 year background checks came about, which are supposedly required before anyone can turn a motor.
British airlines I believe operate under similar stringent background check requirements, and I find it ironic that the police whom are charged with carrying out the law didn't employ similar checks. To me its a lot like the congressman getting back from the 12 martini lunch just in time to vote on the Blood Alchohol Testing for all transport workers. Could you imagine if a security company involved in transporting money operated like that? "Ummmm I'ld like a job driving an armored truck, preferably one with a lot of money in it." And these are harmless humor. Fifth columnists, sign up now...
Come on and lighten up, in this case you just have to giggle atleast a little.
Cheers
Wino