What's this strange use of non-past 〜た in a question?


I've come across a character in a show wondering:

> ...っとは言った物の...どこから手を付けたものか

This was translated as:

> But after all I said, where do we start?

I generally view the 〜た form as past tense, but here the latter does not seem
to be translated this way. Why is that, and what are the rules behind that?

Is it possibly related to [Usage of doubled non-past tense
"た"](https://japanese.stackexchange.com/questions/5356/usage-of-doubled-non-
past-tense-%e3%81%9f)?

