Which of the phrases given below the sentence should replace the word/phrase given below in bold in the sentence to make it grammatically correct? If the sentence is correct as it is given and no correction is required, mark 'No correction required' as the answer.
The Miami Metro police is investigating in the Bay Harbour Butcher case.
1
are investigating into
2
is investigating into
3
are investigating onto
4
is investigating inside
5
no correction required