V into n
II.3 The 'inquire' group
These verbs are concerned with research and inquiry. The prepositional phrase indicates the subject of the research or inquiry.
delve dig enquire inquire look probe pry research
They see no reason to delve into the origins of international economic inequality.
Although he had no criminal record, police are inquiring into some of his business deals.
I told him I would look into the story and get right back to him.