Observed a huge black bommerang shaped UFO the size of 2 football fields hovering & moving slowly over the prison.

Several co-workers and myself observed a huge black bommerang shaped UFO in the sky hovering over the women's prison in Bedford Hills.  The underside of this UFO had five round white lights (one at what seemed to be the front, one at each rear tip and one between the front and tail end of each side of the bommerang shaped UFO).  I was at least the size of two football fields and made no sound except for a very low vibrating hum. As it hovered  approximately 100'over us the hairs on my arms and the back of my neck stood up as if touched by some sort of static electricity.  When it began to move it did so very slowly. Every one passing by us stopped their vehicle to see what my friends and I were looking at.  It was creepy as though the occupants of the UFO knew we were looking at it. It was headed in a SE direction.
Date of the event may be approximate.  PD