キレル - to get angry. Katakana, Hiragana or Kanji?

[Tourne]

Beginner lesson 102 introduces キレル, to get angry, which appears in the vocabulary list (and in WWWJDIC) as Katakana. However in the transcript, when the verb is conjugated, it appears as both きれました and 切れました。

What's the story here? Can it really be written all three ways, depending upon circumstance, or is something wrong somewhere?

[Psy]

It's just a variant, think of it like how English uses italics. キレタ pops out in writing ("SHE'S FLIPPED!") more than just writing 切れた (she's angry). That's all there is to it, really!

[Sean]

You can also write it with both kana scripts, キレる. According to Google, that's the more popular version using kana (1,600,000+ hits compared with under 200,000 for just kana).

切れる gets over 7 million, but that could include other uses of 切れる as well (to be sharp, to cut well, to break [literally, and not in the angry 切れる sense], to run out, etc).