crm_get_group_contacts returns every record duble

Given below is the code snippet executed in Drupal page:

<?php

$group = crm_get_groups($params = array('name' => 'something'));

$contacts = crm_get_group_contacts(&$group[0], null, 'In', null, 0, 25 );

foreach( $contacts as $con ) {
$contact = crm_get_contact( array( 'contact_id' => $con->contact_id ) );
print $contact->display_name;
print "<br />";
}

?>

Runnig this snippet causes CiviCRM API to return the list of contacts right, but every contact in this list is duplicated:

contact1
contact1
contact2
contact2
contact3
contact3
...etc...