In this article, we analyze the fundamental global and local symmetries involved in the action for the free relativistic point particle. Moreover, we identify a hidden local symmetry, whose explicit consideration and factorization utilizing of a Fujikawa prescription, leads to the construction of relativistic propagators that satisfy the Chapman-Kolmogorov identity. By means of a detailed topological analysis, we find three different relativistic propagators (orthochronous, space-like, and Feynman) which are obtained from the exclusive integration of paths within different sectors in Minkowski space. Finally, the connection of this approach to the Feynman checkerboard construction is explored. Contents I. Introduction A. The context B. The relativistic point particle C. General considerations on the explicit form of the PI measure II. The propagator A. Action B. The two step propagator C. The N + 1 step propagator D. Space-like, time-like, orthochronous, and the Feynman propagator E. Comparison to the propagators of the Klein-Gordon field F. Without spatial flip symmetry and Feynmans' checkerboard G. Higher dimensional generalization of the propagator H. Higher dimensional generalization of the checkerboard? III. Conclusion Acknowlegements Appendix References