proper colon use

The rules for colon use are not dependent upon the nature of the primary sentence. Colons are used to introduce block quotations and lists. As such, they may follow dependent clauses (or any other acceptable sentence structure).

Sentence fragments are generally discouraged in formal writing, but a fragment followed by a list (each of which completes the sentence) is an acceptable exception to the general rule.

So yes, the colon may be used in either case. But what follows MUST be either a block quotation or a list.

I hope this helps.