Green UFO over a casino in Niagara Falls

On August 19, 2014, during night, a stationary UFO is appeared over a casino, located in Niagara Falls (Ontario). The object looked like a simple green gleam. What is it?

Witness reports:

It appeared at about 1 a.m. after leaving a casino, other search lights were around but were not as clear as this light was. It was stationary. Also it appeared that the rest of it was cloaked, almost rectangular. I've heard about one being reported in the area before, both times on new years eve. There's even videos of it.