  The recent report of X-ray Fe features in the afterglow of the gamma-ray
burst GRB 991216 may provide important clues for identifying the nature of its
progenitor and constraining the burst mechanism. We argue that the strong line
emission can be attributed to the interaction of a continuing (but decaying)
post-burst relativistic outflow from the central engine with the progenitor
stellar envelope at distances less than a light-hour. Only a small mass of Fe
is then required, which could have been readily produced by the star itself.
