diff --git a/js/app.js b/js/app.js
index 4829c6d9..27625def 100644
--- a/js/app.js
+++ b/js/app.js
@@ -250,7 +250,10 @@ OC.Contacts = OC.Contacts || {
 	buildGroupSelect: function() {
 		// If a contact is open we know which categories it's in
 		if(this.currentid) {
-			var contact = this.contacts.contacts[this.currentid];
+			var contact = this.contacts.findById(this.currentid);
+			if(contact === null) {
+				return false;
+			}
 			this.$groups.find('optgroup,option:not([value="-1"])').remove();
 			var addopts = '', rmopts = '';
 			$.each(this.groups.categories, function(i, category) {
@@ -487,7 +490,11 @@ OC.Contacts = OC.Contacts || {
 
 		$(document).bind('status.group.contactadded', function(e, result) {
 			console.log('status.group.contactadded', result);
-			self.contacts.contacts[parseInt(result.contactid)].addToGroup(result.groupname);
+			var contact = self.contacts.findById(self.currentid);
+			if(contact === null) {
+				return false;
+			}
+			contact.addToGroup(result.groupname);
 		});
 
 		// Group sorted, save the sort order
@@ -643,7 +650,11 @@ OC.Contacts = OC.Contacts || {
 									// Delay each contact to not trigger too many ajax calls
 									// at a time.
 									setTimeout(function() {
-										self.contacts.contacts[id].addToGroup(groupName);
+										var contact = self.contacts.findById(id);
+										if(contact === null) {
+											return true;
+										}
+										contact.addToGroup(groupName);
 										// I don't think this is used...
 										if(buildnow) {
 											self.buildGroupSelect();
@@ -679,7 +690,11 @@ OC.Contacts = OC.Contacts || {
 							// at a time.
 							setTimeout(function() {
 								console.log('adding', id, 'to', groupName);
-								self.contacts.contacts[id].addToGroup(groupName);
+								var contact = self.contacts.findById(id);
+								if(contact === null) {
+									return true;
+								}
+								contact.addToGroup(groupName);
 								// I don't think this is used...
 								if(buildnow) {
 									self.buildGroupSelect();
@@ -705,7 +720,11 @@ OC.Contacts = OC.Contacts || {
 					if(result.status === 'success') {
 						var groupname = $opt.text(), groupid = $opt.val();
 						$.each(result.ids, function(idx, id) {
-							self.contacts.contacts[id].removeFromGroup(groupname);
+							var contact = self.contacts.findById(id);
+							if(contact === null) {
+								return true;
+							}
+							contact.removeFromGroup(groupname);
 							if(buildnow) {
 								self.buildGroupSelect();
 							}
diff --git a/js/contacts.js b/js/contacts.js
index 61b0c403..08533e53 100644
--- a/js/contacts.js
+++ b/js/contacts.js
@@ -1407,32 +1407,44 @@ OC.Contacts = OC.Contacts || {};
 			$('tr.contact:not(:visible)').show();
 			return;
 		}
-		for(var contact in this.contacts) {
-			contact = parseInt(contact);
-			if(contacts.indexOf(contact) === -1) {
-				this.contacts[contact].getListItemElement().hide();
+		for(var id in this.contacts) {
+			var contact = this.findById(id);
+			if(contact === null) {
+				continue;
+			}
+			if(contacts.indexOf(id) === -1) {
+				contact.getListItemElement().hide();
 			} else {
-				this.contacts[contact].getListItemElement().show();
+				contact.getListItemElement().show();
 			}
 		}
 	};
 
 	ContactList.prototype.contactPos = function(id) {
-		if(!id) {
-			console.warn('id missing');
-			return false;
+		var contact = this.findById(id);
+		if(contact === null) {
+			return 0;
 		}
-		var $elem = this.contacts[parseInt(id)].getListItemElement();
+		
+		var $elem = contact.getListItemElement();
 		var pos = $elem.offset().top - this.$contactList.offset().top + this.$contactList.scrollTop();
 		return pos;
 	};
 
 	ContactList.prototype.hideContact = function(id) {
-		this.contacts[parseInt(id)].hide();
+		var contact = this.findById(id);
+		if(contact === null) {
+			return false;
+		}
+		contact.hide();
 	};
 
 	ContactList.prototype.closeContact = function(id) {
-		this.contacts[parseInt(id)].close();
+		var contact = this.findById(id);
+		if(contact === null) {
+			return false;
+		}
+		contact.close();
 	};
 
 	/**
@@ -1443,6 +1455,17 @@ OC.Contacts = OC.Contacts || {};
 	* to load the requested contact if not in list.
 	*/
 	ContactList.prototype.findById = function(id) {
+		if(!id) {
+			console.warn('id missing');
+			console.trace();
+			return false;
+		}
+		id = parseInt(id);
+		if(typeof this.contacts[id] === 'undefined') {
+			console.warn('Could not find contact with id', id);
+			console.trace();
+			return null;
+		}
 		return this.contacts[parseInt(id)];
 	};
 
@@ -1519,7 +1542,11 @@ OC.Contacts = OC.Contacts || {};
 		}
 
 		// Let contact remove itself.
-		self.contacts[id].destroy(function(response) {
+		var contact = this.findById(id);
+		if(contact === null) {
+			return false;
+		}
+		contact.destroy(function(response) {
 			console.log('deleteContact', response);
 			if(response.status === 'success') {
 				delete self.contacts[id];
@@ -1542,10 +1569,13 @@ OC.Contacts = OC.Contacts || {};
 	* @returns A jquery object to be inserted in the DOM.
 	*/
 	ContactList.prototype.showContact = function(id, props) {
-		console.assert(typeof id === 'number', 'ContactList.showContact called with a non-number');
+		var contact = this.findById(id);
+		if(contact === null) {
+			return false;
+		}
 		this.currentContact = id;
-		console.log('Contacts.showContact', id, this.contacts[this.currentContact], this.contacts);
-		return this.contacts[this.currentContact].renderContact(props);
+		console.log('Contacts.showContact', id, contact, this.contacts);
+		return contact.renderContact(props);
 	};
 
 	/**