Ethical Hacker to identify the owner of an Instagram account

I need to gain information that will lead me to know who runs a certain Instagram account (which has been set up to harass people in my organization). All I have is the account name and the first and last digits of their email address. Ideally I need their real name, but also would like to acquire their phone number or full email address to positively link them to managing the account. I will need some kind of evidence, even just a screenshot of the positive findings.