On Thursday, the Mississippi Supreme Court ended any more appeals, denying the state's motion to reconsider a November 2010 decision that the case should be tried again.
"I'm very happy about it," said Oxford attorney David Hill, who has represented Williams and his parents in appealing his 2007 conviction and life sentence.
A Lafayette County jury convicted him in the death of Demetria Bracey of Jackson.
In 2005, Williams and Bracey were students at the University of Mississippi when she was found stabbed to death in a closet in Williams' Oxford apartment.
He claimed her death was part of a suicide pact that he couldn't finish on himself.
In ordering Williams' new trial, Presiding Justice George C. Carlson Jr. wrote that the court record showed conflicting expert testimony about whether Bracey killed herself.
Carlson also said that trial judge Andrew K. Howorth was wrong to refuse to give jurors an instruction that they could consider assisted suicide as well as murder as the cause.
"We do find that Williams' statement to law enforcement, which were offered into evidence," the justice wrote, "combined with the other evidence in the record concerning the interactions between Williams and Bracey - indicate that a hypothetical reasonable juror may have believed Williams' version of events."
The maximum punishment for murder is life in prison, and for assisted suicide it's 10 years.
Hill said he expects the case to be back on the Lafayette Circuit Court docket soon.
He also said Williams' parents were informed about the court's decision soon after it became public Thursday and he expects to speak with them today.
Williams, now 27, is serving his life sentence in a Meridian prison medical facility.
Contact Patsy Brumfield at (662) 678-1576 or email@example.com.