Help with header email-address redirecting

I’ve implemented a script which will redirect the email-address request by using headers.

This works fine in Chrome and Firefox, however in IE the script will load the email client twice and after that display a blank page.

How do I edit the script so that it only displays the client once and returns the user to the page from which the reequest was made?

if (isset($_GET['staffMember'])) {
	add_action('template_redirect', 'func_staffMail');
}

function func_staffMail() {
	$user_ID = htmlspecialchars($_GET['staffMember']);
	$user_info = get_userdata($user_ID);
	$user_mail = $user_info->user_email;
	if ($user_info) {
		$ref = $_SERVER['HTTP_REFERER'];
		header("Location: mailto://{$user_mail}");
		die();
	} else {
		header('HTTP/1.0 404 Not Found');
		die();
	}
}