There is a typo in face_recognition/example/facerec_ipcamera_knn.py
diff --git a/examples/facerec_ipcamera_knn.py b/examples/facerec_ipcamera_knn.py
index ae9223416..55623ed8f 100644
--- a/examples/facerec_ipcamera_knn.py
+++ b/examples/facerec_ipcamera_knn.py
@@ -209,6 +209,6 @@ def show_prediction_labels_on_image(frame, predictions):
             frame = show_prediction_labels_on_image(frame, predictions)
             cv2.imshow('camera', frame)
             if ord('q') == cv2.waitKey(10):
-                cap1.release()
+                cap.release()
                 cv2.destroyAllWindows()
                 exit(0)

The third last line (line no. 212) is written as cap1.release(). It should be cap.release instead.
cap1.release() > cap.release()