  In this work, we investigate numerical evolution of massive Kaluza-Klein (KK)
modes of a scalar field in a thick brane. We derive the Klein-Gordon equation
in five dimensional spacetime, and obtain the evolution equation and the
Schr\"odinger-like equation. With the resonances of the scalar KK modes as the
initial data, the scalar field is evolved with the maximally dissipative
boundary condition. The results show that there are scalar KK resonant
particles with long life on the brane, which indicates that these resonances
might be viewed as one of the candidates for dark matter.
