FRESNO, Calif. (KFSN) -- Testimony is getting underway in the trial of a Fresno man accused of killing a two-year-old boy.
Nearly two years after Xander Villalobos's death, his alleged killer is on trial.
Prosecutors say his October 2021 death was at the hands of his mother's then-boyfriend, Aaron Moton.
Xander's mother, Nikkey Rojas, took the stand Tuesday.
The district attorney asked about the hours leading up to her son's death.
"He was going to a birthday party that day at his grandparent's house," recalled Rojas.
"He being Xander? So, what was the plan?" asked the district attorney.
"The plan was I was going to drop Xander off. We were going to drop him on our way to work 'cause it's the same direction," Rojas answered.
While Rojas was getting ready for work, she said Moton was alone with Xander in another room, preparing him for the party.
It was after that she said her son's behavior changed.
"He was a little limp. Kinda like not holding himself up," said Rojas.
"Was his head droopy?" asked the district attorney.
"A little bit," Rojas responded.
Confused and concerned, she said she first called her sister, who pushed her to call 911.
That call played back in court.
Coroners determined Xander, who was just days shy of his 3rd birthday when he died from a completely lacerated liver.
He also suffered injuries to his head and spinal cord.
While Rojas points the finger at her former boyfriend, his defense claims she may have also had time alone with her son that afternoon.
"He had to get ready, too. He had to brush his hair, his teeth, and all that kind of stuff, right?" said defense attorney Scott Kinney.
"Yeah," Rojas replied.
"So, at that point in time, you were alone with Xander, right?" asked Kinney.
"I was in my bedroom. Xander was in the living room," Rojas responded.
Moton does have a prior misdemeanor domestic violence conviction, and Rojas says that his temper was apparent in their relationship and even boiled over to physical abuse months before Xander's death.
"We were in the bathroom arguing, and he choked me, put me against the wall," Rojas recalled.
In court on Tuesday, she said she never worried that abuse would extend to her children and that Moton had stepped into the father role for her son, taking care of him while she worked.
Moton is charged with murder and assaulting a child, causing death.
He could spend 25 to life in prison if convicted on all charges.
The district attorney expects the trial to last at least through the end of the week.