I work as a security guard so observation is something that is in my second nature because of that job. Not long ago I was at work (alone) and the place where I was, there where absolutely no people present.
It was a building with some offices, and they had a problem with their alarm system. The motion detectors seemed to get activated constantly without anyone being there, so they shut it down and let us come to secure the place until the alarm company came to fix it.
While I was sitting there doing some stuff on the computer a cardboard sign suddenly tipped over. I went to check it but I could not find why it did that. There was nobody there that could have touched it, there was no draft in the building.
Behind the desk where I was sitting was a staircase, the staircase was locked down because they where working in the building and there was no stair (they where in the process of placing a new one)
Suddenly I heard footsteps on the stairs, this could not be the case because there where no stairs at that moment.
So I unlocked the door where the staircase was to check the sound and while I was looking down I saw a sort of white transparent figure going away from the hole. To be honest, I was kind of freaked out in my mind. What have I seen, where it came from I do not know.
Unfortunately due to the lack of the stairs I could not go and investigate it (and at that moment I was too freaked out to do so I think:p)
After this happening I started to get more interested in the paranormal and I started to research some things. I have found out who the owner of the building was and how to contact him. I contacted him (anonymously, so I would not harm the security company I work for if he thinks I was crazy). This is the answer I received from him by email (I translated it myself in English)
Can I ask you the reason for asking about spiritual history of the building. I can only imagine you doing this because someone has told you that there is a ghost in our basement.
The building has been in my family for a long time. There have been reports of people, including me that have seen and heard strange things. The basement of the building is a place where strange things happen, and also the entrance to the basement has a strange feel to it.
In 1928 a servant of the family fell down the stairs to the basement, broke her neck and died at the bottom of the stairs. Many believe that now she haunts the building.
I can not give you further details about this event as this is all that has been told to me about it, but since I have had some experiences here in the house I tend to believe the story.
At the moment I read this the mail I got shivers down my spine, the only explanation I can give to the "thing" I have seen is that it was the spirit of the lady who died there. Was it her, was it someone or something else, I will never know I guess.
I mailed the man back to ask if it was possible to send an investigation team to the building, but that is something he could not allow.