I can't help but wonder who the knife wielding attackers trained with to learn their edged weapons techniques?
Certainly it had to be someone? You can't just pick up a boning knife, or a filet knife, or a cleaver and just whack 30 folks, can you???
They had to have specific instruction. Perhaps YouTube or bootleg DVD training programs?
And they certainly had to have custom designed and made knives! Off the shelf Chinese or Vietnamese "knives" simply couldn't do this kind of damage!
I'm glad we live in the U.S. where if we're attacked we can bet our attackers are at least semi professionally skilled and trained...and use the best the cutlery industry has to offer.