diff --git a/include/acl_selectors.php b/include/acl_selectors.php
index ee74ccc16a..90c9a35d4f 100644
--- a/include/acl_selectors.php
+++ b/include/acl_selectors.php
@@ -382,7 +382,7 @@ function acl_lookup(&$a, $out_type = 'json') {
 	$count = (x($_REQUEST,'count')?$_REQUEST['count']:100);
 	$search = (x($_REQUEST,'search')?$_REQUEST['search']:"");
 	$type = (x($_REQUEST,'type')?$_REQUEST['type']:"");
-	
+	$conv_id = (x($_REQUEST,'conversation')?$_REQUEST['conversation']:null);
 
 	// For use with jquery.autocomplete for private mail completion
 
@@ -450,6 +450,7 @@ function acl_lookup(&$a, $out_type = 'json') {
 		$contact_count = 0;
 	}
 	
+	
 	$tot = $group_count+$contact_count;
 	
 	$groups = array();
@@ -553,6 +554,44 @@ function acl_lookup(&$a, $out_type = 'json') {
 		
 	$items = array_merge($groups, $contacts);
 
+	if ($conv_id) {
+		/* if $conv_id is set, get unknow contacts in thread */ 
+		$unknow_contacts=array();
+		$r = q("select 
+					`author-avatar`,`author-name`,`author-link`
+				from item where parent=%d
+				and (
+					`author-name` LIKE '%%%s%%' OR
+					`author-link` LIKE '%%%s%%'
+				)", 
+				intval($conv_id),
+				dbesc($search),
+				dbesc($search)
+		);
+		if (is_array($r) && count($r)){
+			foreach($r as $row) {
+				// nickname..
+				$up = parse_url($row['author-link']);
+				$nick = explode("/",$up['path']);
+				$nick = $nick[count($nick)-1];
+				$nick .= "@".$up['host'];
+				// /nickname
+				$unknow_contacts[] = array(
+					"type"  => "c",
+					"photo" => $row['author-avatar'],
+					"name"  => $row['author-name'],
+					"id"	=> '',
+					"network" => "unknown",
+					"link" => $row['author-link'],
+					"nick" => $nick,
+					"forum" => false
+				);
+			}
+		}
+
+		$items = array_merge($items, $unknow_contacts);
+		$tot += count($unknow_contacts);
+	}
 
 	if($out_type === 'html') {
 		$o = array(
diff --git a/js/fk.autocomplete.js b/js/fk.autocomplete.js
index 2334bb4a2c..cf6fd25cbc 100644
--- a/js/fk.autocomplete.js
+++ b/js/fk.autocomplete.js
@@ -14,6 +14,11 @@ function ACPopup(elm,backend_url){
 	this.kp_timer = false;
 	this.url = backend_url;
 
+	this.conversation_id = null;
+	var conv_id = this.element.id.match(/\d+$/);
+	if (conv_id) this.conversation_id = conv_id[0];
+	console.log("ACPopup elm id",this.element.id,"conversation",this.conversation_id);
+
 	var w = 530;
 	var h = 130;
 
@@ -67,6 +72,7 @@ ACPopup.prototype._search = function(){
 		count:100,
 		search:this.searchText,
 		type:'c',
+		conversation: this.conversation_id,
 	}
 	
 	$.ajax({
@@ -79,8 +85,10 @@ ACPopup.prototype._search = function(){
 			if (data.tot>0){
 				that.cont.show();
 				$(data.items).each(function(){
-					html = "<img src='{0}' height='16px' width='16px'>{1} ({2})".format(this.photo, this.name, this.nick)
-						that.add(html, this.nick.replace(' ','') + '+' + this.id + ' - ' + this.link);
+					var html = "<img src='{0}' height='16px' width='16px'>{1} ({2})".format(this.photo, this.name, this.nick);
+					var nick = this.nick.replace(' ','');
+					if (this.id!=='')  nick += '+' + this.id; 
+					that.add(html, nick + ' - ' + this.link);
 				});			
 			} else {
 				that.cont.hide();