The envelope

Person x sits in a plain badly light grey interrogation room, looking at a clock impatiently he waits nervously tapping his knees with his thumb. All of a sudden someone bursts into the room with an envelope addressed to “Detective X” in their hand. The envelope is then handed over and the contents are never revealed, person x then walks out of the room in deep thought, stops suddenly by the outside of the door and cries with rage and slams his hand into the wall. He looks up and begins to walk intensely down the corridor before him. Person x stops for thought, reaches into his pocket and realises the envelope is not there, he searches his clothes franticly for the envelope exclaiming by shouting in fear of losing it. Person x the envelope, where is it? Person x reappears in the original space as scene one and goes back to where they were originally sat to look for the envelope but it isn't there, only a note left behind which says “Check mate.”