The father and mother of 8-year-old Xzayvion Riley still face first-degree murder charges but not the death penalty in the boy's 2012 beating death, the East Baton Rouge Parish District Attorney's Office said Tuesday.

Assistant District Attorney Will Morris made the announcement during a hearing in the criminal case of Michael Robertson, 51, and Lavaughn Riley, 37, who have pleaded not guilty.

Morris told state District Judge Don Johnson that prosecutors won't seek the death penalty against Robertson or Riley in an effort to expedite the 5-year-old case. Both defendants were in the courtroom, Robertson in an orange East Baton Rouge Parish Prison jumpsuit and Riley in green Parish Prison clothes.

Jim Craig, one of Robertson's attorneys, called the state's decision "a first step forward in proving Mr. Robertson is not guilty of the murder of Xzayvion Riley."

"When a child dies, the father is often the scapegoat," he said in a written statement provided to The Advocate outside the courtroom. "Later the father is exonerated when the appeals courts decide that the evidence pointed to a freak set of circumstances that caused the death.

"Michael Robertson is not a monster. He loves children and has often been asked to care for them. He did not kill his son, who he loved," Craig added.

Riley gave testimony at a court hearing in 2014 against Robertson, who was her boyfriend at the time of Xzayvion's death at their Baton Rouge home in June 2012. She testified her son feared his father because he would hit and spank the boy to discipline him. Prosecutors have said they've made no deals with Riley or Robertson.

"She's testified against him without a deal," Riley's attorney, Margaret Lagattuta, said Tuesday. "Our impression was it would never be a death penalty for her."

Lagattuta has said previously that Riley's fear of losing her children to the state prevented her from stopping Robertson's alleged abuse of Xzayvion.

"She lives with it every day," Lagattuta said Tuesday. "She's got a lot of guilt."

District Attorney Hillar Moore III noted that after five years of proceedings in the case, there is still no trial date set.

"It's time to get this matter to trial and concluded," he said afterward, adding that the death penalty would have been an appropriate penalty in the case. "I want to see this matter concluded."

Xzayvion's death was classified as a homicide. Coroner's officials found he died of overwhelming infection caused by a ruptured bowel from blunt-force trauma to his abdomen. An autopsy revealed dozens of external signs of recent and past trauma, including a human bite mark on his stomach.

Xzayvion's oldest sister reported seeing Robertson bite her brother on a regular basis as a form of discipline, East Baton Rouge sheriff's officials have said.

Robertson's attorneys are fighting to keep the bite mark evidence out of the hands of a jury, calling it "scientifically unsound," "grossly unreliable" and "junk science."

Morris has argued in court documents that Xzayvion's death was the culmination of an "escalating pattern" of physical abuse.

The Louisiana Supreme Court ruled last year that a jury can hear about the abuse Robertson allegedly inflicted on his son, including injuring the boy's mouth with a belt in 2008, choking him and shoving his head into a toilet in 2010, and breaking his leg in February 2012 — just four months before Xzayvion died.

Riley's 2014 testimony included hearing her son's leg "pop" when Robertson allegedly broke it while the boy tried to get away from him during what she described as horseplay. Xzayvion's oldest sister, however, testified at the same hearing that she never saw Robertson and her brother play together in the years leading up to his death. The girl said she heard Xzayvion's leg pop while her brother was trying to get away from Robertson by crawling under a bed.

"It didn't look like he was having fun," she said of her brother during the incident, adding later that "nobody was smiling, nobody was laughing."

Xzayvion told medical personnel he fell from a bunk bed, but the doctor who operated on the boy testified the broken femur was caused by a twisting of the bone, not a fall.

Riley admitted in her testimony that she beat her son on a previous occasion. Craig has said Xzayvion's hospital records from that incident, also just months before his death, document his request to be protected from his mother.

Following the 2010 incident that the state Supreme Court said could be presented to a jury, Louisiana's child protection agency put a safety plan in place to limit Robertson's involvement with his son, Morris has said. The plan was in place until April 2011.

If convicted of first-degree murder, they would each face mandatory life in prison.

Follow Joe Gyan Jr. on Twitter, @JoeGyanJr.