Investigators say they are following leads to determine the origin of the grenades that were discovered inside a Santa Monica storage area and transported to East L.A. where the explosion occurred Friday morning.

The investigation into the deaths of three L.A. County deputies, all killed by an explosion of military-style grenades thought to be inert, has made its way from Santa Monica to Marina del Rey

This development follows a continuing investigation into an apartment building in Santa Monica, where several devices possibly connected to Friday's explosion were seized on Thursday.