The local, covariant, continuous and off-shell (as well as on-shell) nilpotent (anti-)BRST symmetry transformations are derived for a one (0+1)-dimensional free scalar relativistic particle in the framework of superfield formalism. The trajectory (i.e. the worldline) of the free particle, parametrized by a monotonically varying evolution parameter τ , is embedded in aD-dimensional flat Minkowsk...