A then-4-year-old girl who survived a brutal attack in May 2008 that killed her mother and 3-year-old brother told a detective in a hospital interview that her “daddy and a lady” were with them in a BREC park near Zachary that day and that the lady cut her, her mother and brother, a sheriff’s captain testified Monday.

Dominique Dantoni Smith, the now-9-year-old girl’s father, is standing trial in Baton Rouge on two counts each of first-degree murder and attempted first-degree murder.

Smith, 31, of Wilson, faces a mandatory sentence of life in prison if convicted of first-degree murder because East Baton Rouge Parish prosecutors earlier this month withdrew a notice of intent to seek the death penalty.

Prosecutors made the decision after family members expressed concern about the welfare of the girl, Paige Johnson, who may be called to testify.

Elton Richey, one of Smith’s attorneys, told the 12 jurors and two alternate jurors in his opening statement Monday that Smith — who served with the U.S. Army in Iraq — is innocent and was not even in Doyle’s Bayou Park on Pride-Port Hudson Road on May 4, 2008.

Trendall Lashel Matthews, 25, of Jackson, who was Smith’s girlfriend at the time of the attack, pleaded guilty in 2011 to two counts each of first-degree murder and attempted first-degree murder in return for a life sentence.

She is expected to testify Tuesday against Smith.

Matthews testified at a hearing last month that she watched Smith kill Jessica Johnson Palmer, 23, of Baker, and Juan Palmer Jr., 3, and cut Paige. Matthews said she used her feet to hold Jessica Palmer down.

Paige and Robbyn Palmer, who also was one of Jessica Palmer’s children and was 6 months old at the time, were left overnight in the park for dead.

Prosecutor Darwin Miller described for the jury a scene of “unspeakable horror,” saying Jessica Palmer was nearly decapitated and Juan’s neck was cut from “side to side.” Paige’s throat was cut too, he said.

“It’s unfathomable. It’s unconscionable what happened to this family on May 4, 2008,” Miller said in court.

Heather Morris, who was fishing in the park that day, testified she heard screams coming from a wooded area in the park around 1:30 p.m. but saw or found nothing.

“I heard a woman scream. It was a horrible scream. It was a piercing, horrible scream,” she said through tears. “And I heard some children screaming. I heard a girl scream.”

The jury viewed gruesome crime scene photographs while East Baton Rouge Parish sheriff’s Capt. Ben Odom was on the witness stand.

It was Odom who testified about what Paige told a detective on May 5, 2008 — the day she was found in the park and taken to a hospital. Odom was not at the hospital when the girl was questioned that day.

Smith and Jessica Palmer were once romantically involved and had a child — Paige — together. Matthews and Palmer were cousins. Smith and Palmer were both married, but not to each other, at the time of Palmer’s death. Palmer was separated from her husband.

Smith was the target of a paternity and child-support petition involving Paige, according to West Feliciana Parish court records. Palmer filed the petition against Smith in November 2006.

Richey on Monday called Matthews a “murderess” who was “driven by jealousy.” He told the jury she made a deal to “save her neck” and “sacrificed” Smith.

Miller told jurors he does not expect them to like Matthews.

“Trendall Matthews without a doubt is a killer,” he said.

However, Miller said the state has evidence that corroborates Matthews’ statements.

Sheriff’s detectives have testified previously that Smith implicated himself and Matthews in the attacks.

Smith told detectives he and Matthews bought a baseball bat and lighter fluid before meeting Palmer and her children at the park, according to an arrest affidavit.

Smith said he and Palmer went for a walk, during which he grabbed her hands while Matthews attacked her, the affidavit says.

Smith said he and Matthews purchased new clothes at an area store and used the lighter fluid to burn the clothes they were wearing, the affidavit states.

Richey argued Monday that Smith’s “so-called confession” was false. He said Smith “caved” in under 14 to 15 hours of intense interrogation.