That's 'collected' only in the sense that the evidence has come into existence and legal proceedings have become a possibility. Speaking only for the US and as far as I'm aware, it isn't necessary for the evidence to actually be in the possession of any legal authority or for any legal proceedings to be underway.

Deleting incriminating emails in contemplation of future investigation is tampering with evidence, for example. I won't comment on police video recordings - knowledge and intent play a significant role in whether or not a crime has occurred, here.

I'm no lawyer, but to me, that's an interpretation that's more to-the-letter than in-the-spirit. A savvy judge could conceivably consider evidence collection mechanism tampering a special case of evidence tampering.