Authorities said a desolate corner of San Diego County may be its most violent area. It is so dangerous 10News crews had to put on bulletproof vests before entering the area near Boulevard."The violence in this area is so bad that a 12-year-old was raped to death," said Estela De Los Rios of the Center for Social Advocacy.In the area, authorities said there are pieces of evidence left behind that serve as a grim reminder of the violence happening near the U.S.-Mexico border."They're ruthless; they'll come over here, they'll pick one out that they want, they drag her off onto the rocks, they'll rape her and they just leave them here," said Carl Braun, founder of the Border Patrol Auxiliary, a group that assists U.S. Border Patrol agents.The rapes are committed by the people the victims trust, authorities said. The women and their families give their life savings to human smugglers, only to be hurt by them."What they'll do is they'll get them in sight of the border or right across the border and then they'll demand a form of payment that wasn't agreed to on the front end. They will take them off and then rape them," said Braun.After raping the women, authorities said the smugglers hang their underwear on the trees as trophies to mark their brutal conquests.Braun said he has witnessed a woman being raped but could not help because it happened on the south side of the border."In the morning, we found her undergarments hanging from that stick that's sticking up by the fence there," said Braun.Braun said the violence has now crossed the border into San Diego County.Armed with guns, Braun and his colleague Mike Schmid escorted 10News to a place where they said rapes have happened.A young girl's underwear hanging from a tree and a woman's pair of pants was found on the ground during 10News' journey. Braun said he has also found women wandering lost in the area who just wanted to go home."These people are afraid, these women are in danger, they're afraid for their lives," said Schmid.De Los Rios said most victims are too scared to come forward, and without evidence or witnesses no investigations are ever started."We cannot let children be raped on the border, regardless of what side. It's very sad to know that this is occurring on a daily basis," said De Los Rios.