The Collaborative International Dictionary of English v.0.48:

Police \Po*lice"\, v. t. [imp. & p. p. Policed; p. pr. & vb.
   n. Policing.]
   1. To keep in order by police.
      [1913 Webster]

   2. (Mil.) To make clean; as, to police a camp.
      [1913 Webster]