diff --git a/lib/imap.utilities.js b/lib/imap.utilities.js
index b8bf7e0..9e8bfa7 100644
--- a/lib/imap.utilities.js
+++ b/lib/imap.utilities.js
@@ -365,7 +365,15 @@ exports.buildSearchQuery = function(options, extensions, isOrChild) {
           searchargs += modifier + criteria + ' ' + args[0];
         break;
         default:
-          throw new Error('Unexpected search option: ' + criteria);
+          try {
+            // last hope it's a seqno set
+            // http://tools.ietf.org/html/rfc3501#section-6.4.4
+            var seqnos = (args ? [criteria].concat(args) : [criteria]);
+            exports.validateUIDList(seqnos);
+            searchargs += modifier + seqnos.join(',');
+          } catch(e) {
+            throw new Error('Unexpected search option: ' + criteria);
+          }
       }
     }
     if (isOrChild)