The optical afterglow of GRB 000911: Evidence for an associated supernova?

We present photometric and spectroscopic observations of the late afterglow of GRB 000911, starting similar to1 day after the burst event and lasting similar to8 weeks. We detect a moderately significant re-brightening in the R, I and J lightcurves, associated with a sizable reddening of the spectrum. This can be explained through the presence of an underlying supernova, outshining the afterglow similar to 30 days after the burst event. Alternative explanations are discussed.