diff --git a/lib/index.js b/lib/index.js
index 2a24fb5..64cbe1b 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -28,10 +28,8 @@ UnusedFilesWebpackPlugin.prototype._applyAfterEmit = function(compiler, compilat
 
   glob(this.options.pattern, globOptions, onGlobResult);
 
-  var fileDepsBy = compilation.fileDependencies.reduce(function (acc, usedFilepath) {
-    acc[usedFilepath] = usedFilepath;
-    return acc;
-  }, {});
+  var fileDepsMap = this._getFileDepsMap(compilation);
+
   var absolutePathResolver = Path.join.bind(Path, globOptions.cwd);
 
   function onGlobResult (err, files) {
@@ -39,7 +37,7 @@ UnusedFilesWebpackPlugin.prototype._applyAfterEmit = function(compiler, compilat
       compilation.errors.push(err);
     } else {
       var unused = files.filter(function (filepath) {
-        return !(absolutePathResolver(filepath) in fileDepsBy);
+        return !(absolutePathResolver(filepath) in fileDepsMap);
       });
       if (unused.length) {
         var errmsg = "UnusedFilesWebpackPlugin found some unused files:\n" + unused.join("\n");
@@ -51,5 +49,18 @@ UnusedFilesWebpackPlugin.prototype._applyAfterEmit = function(compiler, compilat
   }
 };
 
+UnusedFilesWebpackPlugin.prototype._getFileDepsMap = function (compilation) {
+  var fileDepsBy = {};
+  compilation.fileDependencies.forEach(function (usedFilepath) {
+    fileDepsBy[usedFilepath] = usedFilepath;
+  });
+
+  Object.keys(compilation.assets).forEach(function (assetRelpath) {
+    var existsAt = this[assetRelpath].existsAt;
+    fileDepsBy[existsAt] = existsAt;
+  }, compilation.assets);
+
+  return fileDepsBy;
+};
 
 module.exports = UnusedFilesWebpackPlugin;