  Using data from the Wide-field Infrared Survey Explorer (WISE) we show that
the mid infrared (MIR) colors of low-luminosity AGNs (LLAGNs) are significanlty
different from those of post-asymptotic giant branch stars (PAGBs). This is due
to a difference in spectral energy distribution (SEDs), the LLAGNs showing a
flat component due to an AGN. Consistent with this interpretation we show that
in a MIR color-color diagram the LINERs and the Seyfert~2s follow a power law
with specific colors that allow to distinguish them from each other, and from
star forming galaxies, according to their present level of star formation.
Based on this result we present a new diagnostic diagram in the MIR that
confirms the classification obtained in the optical using standard diagnostic
diagrams, clearly identifying LINERs and LLAGNs as genuine AGNs.
