Does anyone know how to locate someone with an old po box from over 37 years ago,his name is arnulfo gonzalez?

he goes by the name alan gonzalez alvares, his last know whereabouts was in san jose,he had a son with gaudadlupe gomez,he was in vietnam,he went to san blas,sinaloa,mex .he was arrested in texas for speeding around 1970,i have a picture of him,if anyone can help let me know