Something weird happened yesterday. I was the last one to leave
the office
it was about 10pm. I decided to make one last round to
check everything was in order before I locked up the office.
When I reached the back door, I had an eerie feeling, but that was
it. It is quite common for me to experience such feeling anyway.
There are two locks at the back door, the main lock which can be
lock and unlock from both inside and outside the office. And the
other smaller lock which can only be lock from the inside (We
usually do not lock the second lock)
Anyway, satisfied that everything was in order, I set the alarm,
locked the front/back door and left the office. I was the last one
to leave.
This morning when I came to work, my manger asked me why did I lock
up the back door second lock? She was the first one at the office
and found that the back doors second door was locked (She usually
come by the back door).
But it couldnt be, I am very sure I did not lock up the other lock
yesterday night. And the eerie thing is that this particular lock
can only be locked within the office. Strange
So who locked it up between 10pm - 7am??? 
