A former Santa Clara County jail guard was arrested Monday on suspicion of beating an inmate nearly three years ago, raising concerns about what took so long. The Sheriff’s Office, which oversees the county’s two jails, investigated the incident and asked the District Attorney’s Office in early 2014 to file battery charges against 35-year-old Timmy Tri. Prosecutors declined for unknown reasons, but Tri—who was placed on administrative leave shortly after the incident—stayed on the county payroll for almost two years. He took home $83,000 in salary and overtime in 2014 and $67,000 the next year until his last day on the job in mid-August 2015. A couple weeks after Tri’s last day on the job, an inmate’s death at the Main Jail put the correctional branch into the national spotlight. Three young jailers—Jereh Lubrin, Matthew Farris and Rafael Rodriquez—were charged with murder in connection with Michael Tyree’s fatal beating a year ago. Tyree’s death brought unprecedented scrutiny to the county jails and prompted a series of reforms. A couple months after Tyree died, the DA decided to streamline the way it handles excessive-force complaints against jail deputies by assigning a point person—prosecutor John Chase—to review every single one. When he got to Tri’s case this past spring, Chase did a little more digging, hired an expert witness and filed the charges: assault with a deadly weapon and assault under the color of authority. Chase tells Fly that he has no idea why his office dropped the case the first time. Witnesses of the dispute that took place on Oct. 3, 2013, on the fifth floor of the Main Jail, say that two deputies held down inmate Daniel Jackson while Tri kicked and punched him in the head with skin-splitting, bone-cracking force. Jackson had to get stitches. Tri, whose arrest comes only a few months after his colleagues Phillip Abecendario and Tuan Le were accused of beating another inmate, could spend up to seven years in the clink if convicted.