. >> reporter: herndon is one of 20 people robbed in palo alto since 20th. police told a packed community meeting tonight, while no one was seriously hurt, they're concerned the confrontations may turn violent. >> the one common denominator is firearms are being used. >> reporter: police are stepping up patrols but say it's hard to know where to target enforcement. they're happening all over town, many on dark, quiet residential streets. in nearly every case, the suspects strike twice. police say do what the robbers say especially if a gun is involved. advice herndon said may be hard to follow at the moment. >> he stood in the street and said, "hand over your wallet." i said, "i won't give you my wallet but i'll give you all my cash." i was really mad. >> reporter: investigators hope anger translates into awareness. >> i'm not going to feel different at night. >> reporter: herndon says she's not staying home. now, police say they have made eight arrests connected to six of these cases. and they say that some of the suspects are from out of town and some here