Retrieve emails related to a specifc lead

Hi there,

I am trying to retrieve all the emails associated with a specific lead using rest api.
i use the following code:

$get_lead_email_parameters = array(
‘related_module_link_name_to_fields_array’ => array(),
‘related_fields’ => array(
‘deleted’ => ‘0’,
$get_lead_email = call(‘get_relationships’, $get_lead_email_parameters, $url);

This code works with an opportunity but not with the lead. Why is that so?
Can anyone tell me how do i display all the emails attached with a lead id?

Okay i got it,
outbound emails are attached and not the inbound emails. Inbound emails are not linked directly. I need to a MySQL query to get the inbound emails using parent_id value.