  Type 2 active galactic nuclei (AGN) show signatures of accretion onto a
supermassive black hole through strong, high-ionization, narrow emission lines
extended on scales of 100s to 1000s of parsecs, but they lack the broad
emission lines from close in to the black hole that characterize type 1 AGN.
The lack of broad emission could indicate obscuration of the innermost nuclear
regions, or could indicate that the black hole is no longer strongly accreting.
Since high-energy X-rays can penetrate thick obscuring columns, they have the
power to distinguish these two scenarios. We present high-energy NuSTAR
observations of 9 Seyfert 2 AGN from the IRAS 12 micron survey, supplemented
with low-energy X-ray observations from Chandra, XMM-Newton, and Swift. The
galaxies were selected to have anomalously low observed 2-10 keV luminosities
compared to their [O III] optical luminosities, a traditional diagnostic of
heavily obscured AGN, reaching into the Compton-thick regime for the highest
hydrogen column densities ($N_{\rm H} > 1.5 \times 10^{24}\, {\rm cm}^{-2}$).
Based on updated [O III] luminosities and intrinsic X-ray luminosities based on
physical modeling of the hard X-ray spectra, we find that one galaxy was
misclassified as type 2 (NGC 5005) and most of the remaining AGN are obscured,
including three confirmed as Compton-thick (IC 3639, NGC 1386, and NGC 3982).
One galaxy, NGC 3627, appears to be recently deactivated. Compared to the
original sample the 9 AGN were selected from, this is a rate of approximately
1%. We also find a new X-ray changing-look AGN in NGC 6890.
