helicoptor with a spot light on (posibly a police Jetranger) flying Nth towards us at 100 to 150 ft altitude. ufo makes a non banking 90 turn to west.helicopter turns to follow, spot light did not depict a siloette of object.helicopter contues turn to south and departs. ufo slowly moves off to the west. Only thing visible is 4 lights green,white ed and blue. I dont recall what order,but they flashed from left to right.object estimated to be 50 ft wide. I wish I knew who was flyong that chopper. They were just off the top of it and had a good look. the ufo made no sound.