My parents had the house I grew up in, in Lawrenceville, GA built in 1986. My father has always been very OCD about locking down the house. My mom worked mornings and my brother and I would be at school during the day on weekdays. My father worked nights, so he would be alone at the house most of the day on weekdays. On several occassions he would hear the front door open and slam shut, he would call down to see if it was me or my brother coming home from school and when he received no reply, he would walk downstairs to check and the front door would be totally unlocked. He would check around the house and would always come across nothing.
Another time, my mom was cooking in the kichen. My father has just left to grab something from the store. My turned around to the cat hissing and saw a shadowy figure that proceeded to vanish after moments of her seeing it.
Many nights my brother would wake up screaming and crying because he swore someone else was in our house, my parents would make their rounds around the house and would find nothing.
I never got an eerie feeling or noticed anything myself until we went back to Georgia to visit and decided to pay a visit to our old house, which is now in foreclosure. I took several pictures and didn't notice the face in the window in one particular picture until I brought the camera home and uploaded the pictures to the computer.
The only thing I can think from research is that our house ghost came from the house being built on top of where a person may have been buried or died?