LOS ANGELES (KABC) -- Police are searching for two suspects believed to be tied to at least four robberies at 7-Elevens in the San Fernando Valley overnight.The robberies were reported in Northridge, Chatsworth, Granada Hills and Van Nuys. They all happened within a couple hours of each other.Surveillance video shows the suspects were armed and wore hoodies and masks.They are believed to have been traveling on foot and no vehicle description was available. It was unknown how much money was stolen.No injuries were reported.