The Santa Clara County sheriff’s office arrested three 16-year-old boys Thursday on accusations that they sexually battered a 15-year-old, Audrey Pott, who hanged herself eight days after the attack last fall at a Saratoga party. The lawyer for the girl’s family, Robert Allard, said students shared photos of the attack. The girl posted on Facebook that her life was ruined shortly before she committed suicide, he said.