Secret room

As an normal day I was going to my office but when I reach my office. My boss told me about a case on a village about a girl (anna) who disappeared mysteriously . After the work was finished I went to my apartment and started packing up my clothes and others. So I reached the country and no one was in the road. So I was dropped at my house and I entered the room it was a creepy place but I have no option so I started living and after a few days something was different like some scary voice were coming out from the down floor and I slept quietly but suddenly I remember their is no floor I started having goosebumps and I ran out of the room and sleep with my neighbours . And the next day began so I went back to my house then I thought to take a leave for a few days . I thought that I should ask the owner of this house so i went to the owner . So i asked him ( sir i heard some scary sounds coming from the ground? ) but he refused to tell me. And I went to my home and I thought of searching the secrets hidden behind this house so I search all the house but I found nothing but went I open the carpet laid on the floor their was a secret room so I was scared but when I was trying to opened the door but it was not opening after that i know this door has a keyhole and need a key to open so I went to the owner's house but when I reached their the house was locked and I asked the neighbours about the owner they told the owner has left the house yesterday and he told me to give this to a girl who will visit my house. Can you give me. The neighbour said wait a minute, it's a letter.           

The letter  

Hi I am John I know that you would visit me and I know you found the secret room and you came here for the key the key is in your bed. Please take revenge for me . Bye

so I ran to my house and went to my room and the things he said was true so I took the key and opened the door it was dark inside and I heard someone was crying and I found the switch board and I saw a girl tied in the chair with blood in her mouth so I ask her are you anna she said yes and she also said run away sister the owner of the house is evil he is gonna locked you in this room then suddenly I heard a footsteps and I ran upstairs and I saw the owner I was scared he was trying to killed me so I ran towards my room and I took the gun and shot him he was lay death and I ran to the secret room and untie her and burn the death body of him on the secret room. Now I finally found the truth and now I became a great police officer.