This occurred in March, 1987 in Devon, Exeter, U.K. I have had several strange experiences in the past. I will also say that I am neither a believer or non-believer in paranormal phenomena. I simply do not know.
This happened in my home. My wife and I shared a house with a family. Our downstairs bedroom had a French window and, of course, a door leading to and from the room. In the middle of the night, I awoke feeling cold, and when I opened my eyes I noted both the French window was open and so was the door leading out of the bedroom. Both were locked when we went to bed.
I got out of bed and closed the French window. I then went out of the bedroom and checked the front door. A security alarm was fitted to the door and if it were opened without the alarm being deactivated, the alarm would sound. The chain on the alarm attached to the door had been removed and the door was slightly ajar. I locked the door and reset the alarm and simply returned to bed, although it took me a while to get back to sleep because of what had happened.
Strange though this event was, I did not spend too much time worrying about it the following day. In the afternoon, a policeman called to see my wife and he gave her the sad news that her mother had passed away the previous night in hospital. Apparently, she died at about the same time I experience the happenings the previous night.