  If a black hole formed in a core-collapse supernova is accreting material
from the base of the envelope, the accretion luminosity could be observable in
the supernova light curve. We present results of a fully relativistic numerical
investigation of the fallback of matter onto a black hole in a supernova and
examine conditions which would be favorable for detection of the black hole. In
general, heating by radioactive decays is likely to prevent practical detection
of the black hole, but we show that low energy explosions of more massive stars
may provide an important exception. We emphasize the particular case of SN1997D
in NGC1536, for which we predict that the presence of a black hole could be
inferred observationally within the next year.
