Why was the cap arrested?

Joke submitted by Erich G., Bluffton, S.C.

Bob: Why was the cap arrested?
Joe: I don’t know.
Bob: It was covering for the marker!

Takutanuva says:

July 13, 2011 at 8:30 pm

I don’t get it

Reply
- CRAZY DUDE says:
  
  July 17, 2011 at 9:37 am
  
  Me to
  
  Reply
  - EpicVortex says:
    
    July 20, 2011 at 7:38 am
    
    im totally puzzled on this one…
  - cdl 225 says:
    
    July 20, 2011 at 11:45 am
    
    The cap was arrested because it covered for the marker’s crime. Do you get it now?