Investigators in Amherst, New York, where Linda Yalem was killed, said they were not sure if prosecutors considered indicting their John Doe suspect's DNA to keep the seven other rape cases open.
District Judge Andrew Shaw, who previously sentenced the other two women and seven men who named the rape victim, said the only penalty open to him was a fine.
Meanwhile, Labour MP Maria Fyfe said she and six other Labour colleagues would write an open letter to Tyson demanding he donate his purse money to groups working with rape victims.