The indictment, filed Friday, charges Matthew Kinne with capital murder, which is punishable by the death penalty.
Clayton, a 32-year-old mother of four, was found shot dead in her Oxford home May 19.
Kinne — who, it later emerged, was in a relationship with Clayton — broke into her home prior to the murder, according to the indictment.
Prosecutors were at the Lafayette County courthouse Friday afternoon meeting with members of Clayton’s family, according to the family's attorney, Carlos Moore.
But Moore said prosecutors initially wouldn't tell the family what the grand jury had indicted Kinne on.
"We don’t know if the indictment is for capital murder, we don’t know if it’s for first degree murder or manslaughter," Moore said following the meeting.
An assistant district attorney told WREG he is “not at liberty to release any information on an open investigation.”
At the time, Moore said prosecutors had told the family they wouldn't release more details until next week. But in a surprise reversal, he said they called the family later in the afternoon to tell them of the capital murder charge.
In June, the Clayton family asked the City of Oxford for $5 million to settle a wrongful death claim.
Moore said they plan to file a lawsuit against the city, most likely at the end of September since they’re required to give the city 90 days to offer a settlement.