The streets of San Jose should be a little safer.

That's because police officers have taken down a total of 13 members of two violent gangs this summer that they say have been attacking innocent people. Police have arrested a group of juveniles they've dubbed "Los Mocosos," translated from Spanish slang into "snot-nosed kids "or "brats." Police said the youth were all between the ages of 11 and 17.

Police said the youth would flirt with women in downtown to try to distract them, while a female member of the crew would walk up to victims, punch them and rob them.

"They would just come from behind and (deal) vicious, vicious blows," Sgt. Brian Spears told NBC Bay Area Thursday morning. Once the victim was on the ground, Spears said one suspect would "continue the blows," while the others were "rummage through their pockets."

Officers on their regular beat arrested nine of the crew members in May.

But the violence didn't stop. The midnight shift kept keeping a closer eye on things. That's when they found four men and boys who called themselves the "Squad," walk up to unsuspecting victims and "cold-cock" them if they were walking downtown.

The suspects would take off with watches, purses and other items.

Police were able to arrest those four in June.