  Hydrogen atmosphere white dwarfs with metals, so-called DAZs, require
external accretion of material to explain the presence of weak metal line
absorption in their photospheres. The source of this material is currently
uknown, but could come from the interstellar medium, unseen companions, or
relic planetesimals from asteroid belt or Kuiper belt analogues. Mid-infrared
photometry of these white dwarfs provide additional information to solve the
mystery of this accretion and to look for evidence of planetary systems that
have survived post main sequence evolution. We present {\em Spitzer} IRAC
photometry of five DAZs and search for excesses due to unseen companions or
circumstellar dust disks. Three of our targets show unexpected {\em deficits}
in flux, which we tentatively attribute to absorption due to SiO and CO.
