Isn't it true that a haunting can be ociated with the land?

This is going to be long, fair warning. My aunt and I clean at a physical therapy building. We are also good friends with the lady who owns it. Strange things have happened there, even the owner has had experiences. She is a well educated, no nonsense type of woman and even she believes the place is haunted. Just last night we were there and I heard a man talking and then the hall door shut hard. I thought someone had come in after us and my aunt was talking to him. (we keep the doors locked and there is an alarm system but, the owner's husband and some of the workers have keys so it would have been quite possible that someone else was there.) My aunt was no where near that door and was not talking to anyone. A little later downstairs I could have sworn I heard a man's voice again and the name John. Another time when I was there alone I heard a woman's voice very softly saying " Jack, I'm home". The elevator will beep and you can hear it running from the upstairs to the downstairs (or vice versa) and it will open but, no one is on it. We often hear doors opening and closing loudly. As we are gathering garbage upstairs, we usually put the bags on the elevator to take down, one time the bags were already on the elevator and neither my aunt nor I put them on there. Last night when we were taking the garbage to the dumpster I for some reason looked up at one of the windows. I did not actually see anything but, I got shivers all up and down my body. I found out today from my aunt that she too had looked up and got a weird feeling. I am not a nut case, it's not like I am hearing voices all the time, just weird things happen when we are there. ( I do believe I had other paranormal experiences years ago when I was a child) The owner is baffled because she says it is a new building (it was just built a few years ago) But, if there is truly something paranormal there, couldn't it be related to the land it was built on? Like what may have been there a long time ago? I know it's only a movie but, that is how the story goes in "Poltergeist", they built new houses on graveyards. I would appreciate some input on this. Thanks in advance.