Question

The police are - - an investigation into the robbery

Answer 1

in is your answer mate.......

Answer 2

Answer:  

The police are carrying out an investigation into the robbery.

Explanation:

A word that gives names to place, thing, person and idea. It has the ability to do various jobs or functions in a sentence. It still fits the answers to the questions while every time performing above jobs or functions. Subject is a noun that tells us what or whom sentence is about. Direct objects explains the action of some kinds of verbs.