BERKELEY, Calif. (KGO) -- Police in Berkeley say two women and a man are responsible for a spree of violent robberies all within a span of 20 minutes of each other and another robbery happened late Thursday night.A South Berkeley neighborhood was on lockdown as Berkeley police searched for an armed robber. He had just stolen a sandwich from the nearby Berkeley Bowl.Last night, just a few blocks away, police say an unrelated robbery spree started."Any kind of robbery is always worrisome," said Ed Spiller of the Berkeley police department.The robbers struck three times. Two women and one man unsuccessfully first tried to snatch a wallet from a man as he walked down the street. Then they kept going."Looking for people walking by themselves, usually carrying a cellphone, or bag, typical purse snatch, strong-arm robbery," Spiller said.They punched then stole a victim's phone, in West Berkeley. Ten minutes later they robbed a Cal student, as he walked alone, on Spruce Street. He tried to get away but they caught him, pinned him to the ground, and started punching him."That's very terrible, I think after hearing this I am a little scared," said Berkeley resident Wei Ling."It's something you don't want to think about but are aware of now," said Berkeley resident Jennifer Michel.Police have very few leads.