diff --git a/js/libtextsecure.js b/js/libtextsecure.js
index 389dab3409de..a1cb37b1365e 100644
--- a/js/libtextsecure.js
+++ b/js/libtextsecure.js
@@ -38205,7 +38205,7 @@ axolotlInternal.RecipientRecord = function() {
 
                 var i = group.numbers.indexOf(number);
                 if (i > -1) {
-                    group.numbers.slice(i, 1);
+                    group.numbers.splice(i, 1);
                     delete group.numberRegistrationIds[number];
                     return textsecure.storage.axolotl.putGroup(groupId, group).then(function() {
                         return group.numbers;
diff --git a/libtextsecure/storage/groups.js b/libtextsecure/storage/groups.js
index ce1fb862acd4..90154a0fd57a 100644
--- a/libtextsecure/storage/groups.js
+++ b/libtextsecure/storage/groups.js
@@ -86,7 +86,7 @@
 
                 var i = group.numbers.indexOf(number);
                 if (i > -1) {
-                    group.numbers.slice(i, 1);
+                    group.numbers.splice(i, 1);
                     delete group.numberRegistrationIds[number];
                     return textsecure.storage.axolotl.putGroup(groupId, group).then(function() {
                         return group.numbers;