How to get the ID of the "Contact Person" by email?

How to get the ID of the "Contact Person" by email?

Hi,

I need to get the ID of a Contact Person record in Zoho books by its email address. 

When I do a request like
  1. zoho.books.getRecords("Contacts",organizationID,{"email":"sometestemail@here.com"},"zohobooks_custom")

i receive the data about the Company, but not the Contact. And there's not Contact Person ID in this data. 

When I try something like
  1. zoho.books.getRecords("Contact Persons",organizationID,{"email":"sometestemail@here.com"},"zohobooks_custom")
or 
  1. zoho.books.getRecords("Contacts_Persons",organizationID,{"email":"sometestemail@here.com"},"zohobooks_custom")
it says that I am using a wrong API name. 

So what is a proper way to receive the data for the Contact Person (including its ID), not a Contact?