Boom in Duval County, Florida

I am a security officer in Jacksonville, FL. I was on duty in an area know as Deerwood Park. Located in a quickly developing area that was once owned by Skinners Dairy. The area is still heavily wooded. Two weeks ago I was on duty in a building and went outside to smoke a cigarette. I was outside for 5 minutes. I heard a noise like something moving through the tree line. I turned my head toward the noise and the noise stopped. I called on of our vehicle patrols in the area and we moved to the tree line to investigate. We could hear the movement of something very large making very suttle movement. The officer with me and myself felt very uneasy. Laying on the ground 8-10 feet from the tree line was a branch from a pine tree. The needles on the branch were still green.There were no burn marks at the break to indicate lightning had struck. The branch was approximatly 3 inches in diameter and appears to have been broken and then ripped from the tree.What ever it was,sounded as though it moved away from us through the marsh land. This whole incident really creeped me out.On Fri/9-1-00 at about the same time 2:30A.M. The same patrol officer and myself were again standing outside the building I guard. We heard a sonic alarm coming from the building to the north of our location. The patrol officer I was talking to walked back to his car to drive over and investigate. The alarm stopped as though it reset or was deactivated. I informed the patrol officer that it was probably the cleaning crew. As we continued talking about what we were going to do in the gym that mourning. The officer I was talking to turned his head and his eyes got real big. He replyed." Look at that". I turned around and looked toward the tree line and observed nothing. The patrol officer I was talking to sped off in his vehicle in the direction of the trees and I followed on foot. We searched the area and found nothing. The officer told me that he observed heavly built individual who's estimated height was between 7-8 feet in height. The individual appeared all black. The officer I was talking to said when he told me to look, the subject had crossed out of my line of site around another building 100 feet to the south of our location. This officer appeared to be very serious about what he saw. On Sun/9-3-00. I was talking to the other officer who works the same area. He told me of a resident he talked to six months ago,who lives 1 mile to the east of my post. This resident inquired if we did foot patrols through his community? Which was at the time was sparsley populated. When the officer said, "no". The resident continued that a few nights before around dusk he heard a splash in the lake behind his house. What he saw climb out of the lake and walk toward the south and into the trees was exactly what the other officer told me he saw. The resident further stated that this was a regular occurance.