past tense - Is the question "If you didn't break the vase, who did?" a conditional sentence?

My problem is that I was taught (I think wrongly) that whenever a conditional sentence refers to past, there should be past perfect tense in the if clause, as in example 1.

Example 1:

If you hadn't broken the vase, you wouldn't have angered your parents.
[He broke the vase, no doubt about it.]

But is example 2 still a conditional sentence, and is it correct?

Example 2:

If you didn't break the vase, who did?

We're still referring to past, but we don't really know whether he did it or not.

Is this an example of a conditional sentence? Why or why not? How do I recognize a "past" conditional sentence?

Answer

Example 2 means

If you didn't break the vase, then I ask you who did?

The condition is on the speech act of questioning. If you did break the vase, than I needn't ask. Compare:

If you don't mind my asking, who broke the vase?

The condition here is also a condition on my asking the question. This is a general formula -- to be polite, you mention conditions that might make it inappropriate to ask a question.