INQURER: The beleaguered principal of South Philadelphia High resigned Thursday, abruptly ending her controversial tenure after it was revealed that her state certificate was inactive. School officials made the announcement in the afternoon, after The Inquirer asked about the status of LaGreta Brown’s certification to work as principal. The state Department of Education confirmed that the certificate, issued in 2000, was inactive because Brown had not fulfilled a requirement for continuing education. Brown’s resignation, on the day teachers were to take a vote of no confidence against her, ended a turbulent tenure at the 900-student school. On Dec. 3, the school was rocked by racial violence that sent seven Asian students to the hospital. It triggered a boycott and investigations by the district, the state’s Human Relations Commission, and the Department of Justice. MORE