diff --git a/lib/forever-monitor/monitor.js b/lib/forever-monitor/monitor.js
index 5ec901a..ad519c6 100755
--- a/lib/forever-monitor/monitor.js
+++ b/lib/forever-monitor/monitor.js
@@ -369,7 +369,7 @@ Monitor.prototype.kill = function (forceStop) {
       //
       if (this.killTTL) {
         timer = setTimeout(function () {
-          common.kill(self.child.pid, self.killTree, self.killSignal || 'SIGKILL');
+          common.kill(self.child.pid, self.killTree, 'SIGKILL');
         }, this.killTTL);
 
         child.once('exit', function () {