  We analyzed the $^{93}Nb$ on $^{nat}Mg$ reaction at 30 MeV/nucleon in the aim
of disentangling binary sequential decay and multifragmentation decay close to
the energy threshold, i.e. $\simeq 3$ MeV/nucleon. Using the backtracing
technique applied to the statistical models GEMINI and SMM we reconstruct
simulated charge, mass and excitation energy distributions and compare them to
the experimental ones. We show that data are better described by SMM than by
GEMINI in agreement with the fact that multifragmentation is responsible for
fragment production at excitation energies around 3 MeV/nucleon.
