  X-ray fluorescent lines are unique features of the reflection spectrum of the
cold torus when irradiated by the central AGN. Their intrinsic line widths can
be used to probe the line-emitting region. The line widths of the Fe \Ka line
measured from the first order Chandra High Energy Grating (HEG) spectra are
$3-5$ times larger than those measured with the Si \Ka line for Circinus, Mrk
3, and NGC 1068. Because the observed Si \Ka and Fe \Ka lines are not
necessarily coming from the same physical region, it is uncertain whether the
line widths of the Fe \Ka line are over-estimated or not. We measured the
intrinsic line widths of the Fe \Ka line of several nearby bright AGN using the
second and third order Chandra HEG spectra, whose spectral resolutions are
better than the first order data. We found the measured widths are all smaller
than those from the first order data. The results clearly show that the widths
of the Fe \Ka line measured from the first order HEG data are over-estimated.
It indicates that the Fe \Ka lines of the studied sources are originating from
regions around the cold dusty torus.
