How to emphasize a quote is written, not spoken?

Question

In a similar question on EL&U, I asked about suggestions for indicating that a quote is written instead of spoken.

Robusto's answer suggested several possible approaches:

• For longer quotes of written text, use a form of block quote

• Shorter sections can be highlighted in a special font or all caps

  DO NOT ENTER, the sign seemed to scream at me as I approached.

My first thought was to simply italicize the quoted text:

I know who the killer is, she wrote, but she never managed to send her message.

I wanted to pose this question to this community, as it relates to writing style more than the formal conventions of English.

What approach would you recommend?

Answer 1

I like the italics. No justification of that, just - a vote. It seems clearest to me.

Answer 2

As someone who is opposed to using punctuation in non-standard ways to emphasize quotes and who prefers using words to explain what's going on, I say you should skip the italics. Let the story clearly indicate that what the reader is reading is written communication.

Breathing heavily she plunked leaned over her desk and grabbed a pen from the wicker container. I know who the killer is, she scribbled, but that was all that was all she got to write.

If your readers can't understand what the source of the quote is when reading it aloud I don't think you've communicated as well as you possibly could.

In the case of longer quotes, perhaps quoting an entire letter, I could see an inline block quote simply because it's standard in writing.