One of Michael Robertson’s attorneys accused prosecutors Friday of “character assassination” in their attempt to use at Robertson’s future first-degree murder trial evidence of alleged incidents of abuse leading up to the 2012 death of his 8-year-old son, Xzayvion Riley.

East Baton Rouge Parish prosecutors claim Robertson injured Xzayvion’s mouth with a belt in 2008; choked him and shoved his head into a toilet in 2010; broke his leg in February 2012; and repeatedly punched him outside Pierson’s Brilliant Minds Learning Center in April 2012, just two months before the youngster was beaten to death, allegedly by his father.

“They do look damaging because they are damaging. Each of these incidents gets worse and worse and worse and worse,” Assistant District Attorney Will Morris argued Friday to state District Judge Don Johnson. “It’s an escalating pattern of abuse” that the jury should hear, Morris said.

Jim Craig, an attorney for Robertson, described the alleged incidents as “a bunch of dirt thrown against the wall” that could lead a jury to conclude “where there’s smoke there’s fire.”

“That is straight up character assassination,” he told the judge. “None of these incidents should come into evidence.”

Johnson said he will rule May 1 on the admissibility of the so-called evidence of other bad acts.

Robertson, 49, and Xzayvion’s mother, Lavaughn Riley, 35, each are charged with first-degree murder in the boy’s death on June 12, 2012. Robertson was Lavaughn Riley’s boyfriend at the time.

Dr. Beau Clark, the East Baton Rouge coroner, ruled Xzayvion’s death a homicide, concluding he died of “overwhelming infection” caused by a ruptured bowel from blunt-force trauma to his abdomen. An autopsy revealed 60 external signs of recent and old trauma, including abrasions, bruises and a human bite mark.

Robertson has denied any involvement in his son’s injuries, sheriff’s officials have said.

Xzayvion’s oldest sister told deputies that Robertson beat her brother with his fist the day before he died, according to an affidavit of probable cause. She also said she saw Robertson bite the boy regularly to discipline him, sheriff’s officials have said.

Craig argued Friday that law enforcement investigated only two of the alleged incidents of abuse, and no charges were filed against Robertson.

Xzayvion told a teacher in November 2008 that his father put a belt to his mouth and moved it from side to side, leaving abrasions on each side of his mouth that teachers noticed. Robertson denied any wrongdoing, saying he was “rough-housing” with Xzayvion when the boy started to fall off the bed, so he grabbed him by the collar of his T-shirt, which got caught on the boy’s mouth.

Xzayvion also told state workers in August 2010 that Robertson choked him and shoved his head into a toilet, leaving abrasions on his neck that teachers noticed and reported. After that incident, a safety plan was put in place by the state Department of Children and Family Services to limit Robertson’s involvement with his son, Morris has said. The plan was in place until April 2011.

“Was the incident proved? No,” Craig argued Friday.

Riley testified at a pretrial hearing in July that she heard her son’s leg pop in February 2012 while he tried to get away from Robertson during what she described as horseplay. Xzayvion’s oldest sister, however, testified in August that her brother and Robertson were not playing when her brother tried to crawl under a bed to flee from Robertson.

“There is absolutely no proof whatsoever that Xzayvion’s leg was intentionally broken,” Craig said Friday, noting that the boy told a nurse he was afraid of his mom. Riley testified she had beaten her son two weeks before he broke his leg.

Morris noted that the bone Xzayvion broke, the femur, is the largest and heaviest bone in the human body.

“You can’t cause that injury accidentally,” the prosecutor argued. Dr. Joseph Broyles testified in July that the boy’s broken leg was caused by a twisting of the bone.

Brilliant Minds Learning Center owner Evelyn Pierson also testified in July that she witnessed Robertson punching Xzayvion in the parking lot of her facility two months before he died, but she did not report what she saw.

Craig on Friday charged that Pierson lied.

“What motive would she have to lie?” Morris asked. “She had every reason not to come in here and say what she said.”

Prosecutors have not said whether they intend to seek the death penalty against either Robertson or Riley, who will be tried separately.

Follow Joe Gyan Jr. on Twitter, @JoeGyanJr.