Apache heli flying 300-500 feet above ground seemed to be following something

This is not exactly a UFO report but suspicious activity occurring at around 13:30, give or take a few minutes,  I hear a loud "buzzing", which is not odd as I live in less than a quarter mile from a small airport.  So frequently I am looking out the door to see Planes and Helicopters flying by.
Usually they are civilian aircraft or medical aircraft, but this time it was a Boeing AH-64 Apache helicopter that seemed to be following something(I could not visibly see anything but it was much to low to be just flying by).  There were no markings, just a grayish black chopper with a mounted gun clearly visible as the chopper was no more than 300-500 feet off the ground.  Which is quite low for the Heli's in this area, and this is not the first sign of a military presence in the area.  I have also seen a Boeing Ch-47 Chinook flying by, this one flying much higher then the AH-64 I saw today.