Here's a typical helo searchlight.

http://www.spectrolab.com/searchlights/products/prod_sx16_ns.html

Check the data sheet and.it's 30-40 million candlepower.

With any atmospheric haze/fog, there's be a cone of visual haze beneath the alleged helo.

It would also light up the ground beneath it. Are we seeing the surface of the lake illuminated?

Also, the most recent claims are the pilot was using NVG.

Anyone who has used NVG (including gen3+) knows that a flashlight in the area will overwhelm the visual field. There was enough light scatter to illuminate the body of whatever it was. That would swamp NVG.

We have the atmospheric data so know roughly where the scattered deck was. It's also common for EMS to fly somewhere in the 1000-2500' range, so there should be a pretty good trail of light on the ground/surface of the water under its path.

Here are.beamshots of some guys 70000 lumen HID light in fog. The NightSuns are similar (think of night usage by police departments). Color temps are bluer and the beam.does diverge (it's not straight like a "laser beam"

http://www.candlepowerforums.com/vb/showthread.php?395489-14-quot-70-000-lumen-spotlight-project-(with-beamshots)&p=4716058&viewfull=1#post4716058

Not saying it's impossible, but mighty strange