The Dinner Party

The room grows silent as the people come back from the disaster. The different descriptions exclaimed to you made you want to close your eyes and say this was all a dream.
You think to yourself, "Who would do this? How could this night get any-"
And your thought was interrupted by the sudden flicker of lights and the immediate scream of realization.
The starting 7 people in the room (excluding the body in the other room) felt smaller. As you looked around it finally came to you.
There were only 6 people in the room now. The murderer had struck again. What are you going to do now?