We study the fluorescence decay behavior of the S-1(B-1(3u)) electronic state of pyrazine following its excitation from the ground S-0((1)A(1g)) electronic state with a few nanoseconds light pulse. Our probe of the dynamics is the time-dependent Schrodinger equation. We form superpositions of the eight strongest S-1 molecular eigenstates (MEs) of pyrazine with the light pulse, and then compute the total spontaneous emission as a function of time using the known optical properties of the MEs. Both coherent and incoherent contributions to the fluorescence decay have been observed. We find that single exponential decays exist at selected frequencies in the spectrum, corresponding to exact ME resonances. However, most decays are biexponential owing to the off-resonant excitation of many nearby MEs. Even resonant excitation decays become biexponential at high power. Thus, the "enigma" is apparently resolved, the fast component (and its J dependence) in the nanosecond excited fluorescence decay of pyrazine has its origin in the nonlinear light scattering properties of the isolated molecule.