The National Park Service has launched an internal investigation into the actions of some park rangers after the News4 I-Team obtained video that shows possible security risks at some of D.C.’s most famous monuments.

It started when the News4 I-Team received an anonymous DVD in the mail with the words "This must stop" written on it.

The video shows rangers accessing some of the most famous monuments in Washington: above the Lincoln Memorial, inside the Washington Monument and underneath the Jefferson Memorial, Tisha Thompson reported.

But here's why this isn't just your average tourist video. 

"Breaking and entering," one person is heard saying on the video.

People in National Park Service uniforms recorded themselves breaking locks, hopping over construction barriers and picking bolted doors to get into areas all over the greater Washington, D.C., area.