(CNN)Tennis superstar Serena Williams says she found out her sister's killer had been released from prison minutes before her loss to Johanna Konta last month. The 6-1 6-0 defeat to Konta in the opening round of the Silicon Valley Classic was the worst of Williams' 23-year career. In an interview with Time Magazine, the 23-time grand slam champion said she was scrolling through Instagram 10 minutes before her match and learned the killer had been released on parole.