An East Baton Rouge Parish jury was impaneled Friday night in the first-degree murder trial of an East Feliciana Parish man accused in the 2008 killing of his former girlfriend and her 3-year-old son at a BREC park near Zachary.

The jury will hear opening statements and some testimony Monday.

Dominique Dantoni Smith, 31, of Wilson, faces a mandatory sentence of life in prison if convicted on the murder charges.

Trendall Lashel Matthews, 25, of Jackson, who was Smith’s girlfriend in May 2008, 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 against Smith, who faces the same charges.

Prosecutors earlier this month withdrew their notice of intent to seek the death penalty against Smith after family members expressed concern about the welfare of a young girl — Smith’s daughter — who survived the attack despite having her throat cut.

The girl, who was 4 at the time and is now 9, could testify at the trial.

Smith is accused in the deaths of Jessica Johnson Palmer, 23, of Baker, and her 3-year-old son, Juan Palmer Jr., at Doyle’s Bayou Park on Pride-Port Hudson Road. Smith’s then-4-year-old daughter and her then-6-month-old sibling were left overnight for dead but survived.

Daryl Gold, one of Smith’s attorneys, said Friday that roughly three-dozen prospective jurors were excused earlier in the week due to their familiarity with the case.

Matthews testified at a hearing last month that she watched Smith kill Jessica Palmer and Juan Palmer Jr. and cut Palmer’s daughter, Paige Johnson. Smith and Jessica Palmer were once romantically involved and had a child — Paige — together.

Matthews and Jessica Palmer were cousins.

Sheriff’s Office 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.

At Matthews’ guilty plea hearing in June 2011, prosecutor Darwin Miller said an altercation and argument erupted involving Smith, Palmer and Matthews. He said Smith knocked Palmer to the ground and cut her throat. While Palmer was on the ground, the prosecutor said, Matthews used her feet to hold Palmer down while Smith continued to cut her.