Footsteps in the attic

When I was lying in bed last night, I heard footsteps in the attic. At first I thought it was my mind. After a little while I found out it wasn't my mind so I shut my door and I tried to ignore it but it wouldn't go away! I got up and hit the ceiling with the broom and it still didn't stop! I went to the pull down stairs that led to the attic I pulled the string and the stairs fell out. Bats flew out and were everywhere! Then while the bats were flying I saw two big boots coming down the stairs! I didn't stay to see the rest of the human or thing. I called 911 and the police came immediately. They checked the whole house and said nothing was out of the ordinary and they left. I knew whatever that was it would be back. The next night I was trying to go to sleep when I heard footsteps in the attic...