diff --git a/lib/mongoHandler.js b/lib/mongoHandler.js
index bcb4849..370e32a 100644
--- a/lib/mongoHandler.js
+++ b/lib/mongoHandler.js
@@ -67,7 +67,7 @@ MongoStore._filterElementToMongoExpr = function(filterElement) {
     ">": { $gt: value },
     "<": { $lt: value },
     "~": new RegExp("^" + value + "$", "i"),
-    ":": new RegExp(value)
+    ":": new RegExp(value, "i")
   }[filterElement.operator];
   return mongoExpr;
 };