  Neutron scattering is used to study
NiCl$_{2-2x}$Br$_{2x}\cdot$4SC(NH$_2$)$_2$, $x=0.06$, a bond-disordered
modification of the well-known gapped $S=1$ antiferromagnetic quantum spin
system NiCl$_{2}\cdot$4SC(NH$_2$)$_2$. The magnetic excitation spectrum
throughout Brillouin zone is mapped out at $T=60$ mK using high-resolution
time-of-flight spectroscopy. It is found that the dispersion of spin excitation
is renormalized, as compared to that in the parent compound. The lifetime of
excitations near the bottom of the band is substantially decreased. No
localized states are found below the gap energy $\Delta\simeq0.2$ meV. At the
same time, localized zero wave vector states are detected above the top of the
band. The results are consistent with a more or less continuous random
distribution of bond strengths, and a discrete, possibly bimodal, distribution
of single-ion anisotropies in the disordered material.
