Beads Taken Off by Ghost?

Beads Taken Off by Ghost?
    Here's the gist. My best friend (chrissy) has a ghost that came to her door a couple of times and it really freaked her out so one night she put prayer beads on the doorknob and it didn't reappear for the past year. Last friday I went to go changing in her room but the door wouldn't shut because there were things blocking it, so I took the stuff off and put it in her laundry basket. I closed it and started changing (no one was home but chrissy and her step sister), they were all downstairs, and the door opened, I shouted "chrissy, wait, I'm changing" then I closed it back. It immediately opened right back and I said "stop it", then I tried to close it again, I leaned on the door, and I felt the door knob twist so I open it but no one was there. I went downstairs and told them the whole story but they said they were down there the whole time then chrissy asked me: "did you take the beads off the door?" I told her I did, then we all freaked out and sent her step sister upstairs to put it back on. However, they weren't there at first, but when we looked back on the doorknob they were suddenly there again. I know I took everything off the door... It was a scary night.