White teardrop object with lights going on then off with helicopter very close by

At approximately 5:45pm on Friday, December 28th, 2012, I witnessed a helicopter hovering over a white teardrop shaped object.  I estimate the object and helicopter were about a 1/2 mile from me and approximately 800 to 1000 feet high.  Two other helicopters hovered close by.  I would estimate the two other helicopters were a 1/4 mile from the object and helicopter.  One of these other helicopters was north, the other was to the east.
At first, I thought the helicopter was towing the object.  The white object was about the same size as the helicopter.  The white object had at least three small white/yellow lights on top of it.  These lights went out.  The helicopter would move when the object moved; perhaps about a hundred feet at a time.
After about 10 minutes, the object’s lights came back on and when the object moved so did the helicopter.  About 5 minutes later, the other two nearby helicopters flew away from the area. About 5 minutes later, the object’s lights went out again.   By this time, the object and helicopter were within about 100 yards of my position at about the same elevation.  This was when I noticed that the white object was not being towed by the helicopter as it was some yards in front of the helicopter and slightly below it..
Then, about 5 minutes later, the white object emitted a lot of bright white lights and began to move away from the helicopter, which followed the object.  Both craft went behind a tree and when I moved around the tree both the helicopter and object had disappeared.  That’s what truly freaked me out. I scanned the horizon but could not see the helicopter or the object.  I am at lost to explain what the white object was, or how the helicopter and the object seemed to disappear.