Saturday Matinee - The Invisible Terror

Professor Langley stood before the assembled law enforcement team!
"Gentlemen, this latest crime wave has some particular similarities that can only lead to one conclusion!"
"Okay Prof.....tell us what your theory is but we don't have a lot of time....this fiend strikes at the same time each day and it's almost 10 now...that only gives us an hour to get our force out on the street?"
"Yes Chief Brittles... I understand only too well...but you have to understand what you're up against!!! What do we know about him?"
"We know that he strikes at 11pm every night since his reign of terror began....we know that he hasn't been seen by anyone....we know that even when he's surrounded by witnesses he somehow still avoids being identified....we know that he has sexually assaulted both women and men and still we have no clues as to anything about his appearance.....victims claim that they couldn't see their attacker but they could feel him taking his pleasure from them.....Gentlemen this can only lead to one conclusion, as fantastic as it seems, the attacker must be...."
Suddenly the Professor began to choke....his mouth open wide and his eyes wide with terror....his head began to rock back and forth as he gurgled and spit ran from the corners of his mouth!!!
"He's having a seizure!!!" cried the Chief, "Get me a Medic!!!"
The room exploded into activity as the lawmen ran to get aid for the stricken man! His head seemed to be moving back and forth to some kind of rhythm and from his throat there were only guttural moans!
Suddenly he stopped....leaning forward and he gagged and choked but he didn't move and the assembled lawmen stood transfixed as he gasped and then his head fell to the desk....
"Professor are you alright? Can you speak....."
The professor mumbled, it sounded something like an agreement.....
"Professor what were you going to say? What do you think this fiend is?"
The professor watched the back door of the room open and close and he thought about the words whispered for only him to hear...
"Your house....wear something pretty and plenty of lipstick....I'll be there at 11!!!"
"Nothing! I was going to say this was a complete mystery.....I'm as baffled as you are!!! Now if you men will excuse me I'd like to get home to rest!"
"Of course Professor.....Bring a car around and take the Professor home...then let's all get out there and catch this monster!!!!"