根掘り葉掘り（ねほり はほり） is the way you ask pryingly.

「根掘り葉掘り」（ねほり はほり）is used for the way someone tries to find out details about someone else’s private life in an impolite way.

「根堀り」（ねほり） is to dig out all the roots completely and carefully. And 「葉堀り」（はほり） is just added as a wordplay or a rhyme.