  We report the discovery of a strong iron K alpha line in the hard X-ray
selected source CXOJ 123716.7+621733 in the Chandra Deep Field North survey at
z=1.146. The analysis is made possible by the very deep exposure ~2 Ms and low
background of the ACIS detector. The line profile seems to be inconsistent with
a narrow feature. The best fit solution is achieved with a broad line. Most of
the flux in the broad component originates at energies below 6.4 keV with a
shape similar to that expected from emission in the innermost regions of the
accretion disk.
