We explore the origin of mid-infrared (mid-IR) dust extinction in all 20 nearby (z H > 1.5 × 1024 cm-2) active galactic nuclei (AGNs) with hard energy (E > 10 keV) X-ray spectral measurements. We accurately measure the silicate absorption features at ? ~ 9.7 ?m in archival low-resolution (R ~ 57-127) Spitzer Infrared Spectrograph spectroscopy, and show that only a minority (?45%) of nearby Compton-thick AGNs have strong Si-absorption features (S 9.7 = ln (f int/f obs) >~ 0.5) which would indicate significant dust attenuation. The majority (?60%) are star formation dominated (AGN:SB ) >~ 0.5) which would indicate significant dust attenuation. The majority (?60%) are star formation dominated (AGN:SB 9.7 ~ 0-0.3), which is consistent with that predicted by clumpy-torus models. However, on the basis of the IR spectra and additional lines of evidence, we conclude that the dominant contribution to the observed mid-IR dust extinction is dust located in the host galaxy (i.e., due to disturbed morphologies, dust lanes, galaxy inclination angles) and not necessarily a compact obscuring torus surrounding the central engine.
