  We have followed the evolution of multi-mass star clusters containing massive
central black holes by N-body simulations on the GRAPE6 computers of Tokyo
University. We find a strong cluster expansion and significant structural
changes of the clusters. Star clusters with IMBHs have power-law density
profiles $rho ~ r^{-alpha}$ with slopes $alpha=1.55$ inside the influence
sphere of the central black hole. This leads to a constant density profile of
bright stars in projection, which rules out the presence of intermediate mass
black holes in core collapse clusters. If the star clusters are surrounded by a
tidal field, a central IMBH speeds up the destruction of the cluster until a
remnant of a few hundred stars remains, which stays bound to the IMBH for a
long time. We also discuss the efficiency of different detection mechanisms for
finding IMBHs in star clusters.
