UPPER EAST SIDE, Manhattan -- New York City police are conducting an intense search for a suspect or suspects who have fired shots on two previous occasions at a Manhattan high rise.Police sources confirm an NYPD helicopter was on the case Thursday night, flying circles around Roosevelt Island with a spotlight on.It is a sign of just how seriously officers are taking this case, after two different incidents of gunfire hit a luxury apartment building on the Upper East Side.The first time, last Thursday night, a bullet shattered a window on the 14th floor.Late the next night, bullets hit the 32nd floor of the same building.In both cases, police say the shots were fired from the esplanade on Roosevelt Island - 1,400 feet across the East River.On Wednesday night, police released video of a man and a woman on the esplanade In the video, you can see the muzzle flash from a gun.Fortunately, no one has been hurt, but police are racing to find the pair before someone is.